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

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Watsonville Slough
Water Body ID: CAR3051003019981209150043
Water Body Type: River & Stream
 
DECISION ID
126061
Region 3     
Watsonville Slough
 
Pollutant: Escherichia coli (E. coli)
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2018)
Revision Status Revised
Reason for Delisting: Applicable WQS attained; due to change in WQS
Expected TMDL Completion Date: 2035
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is greater than 1 part per thousand (ppt) 95 percent or more of the time, the enterococci bacteria objective applies, and the E. coli objective is not applicable.

The 95th percentile of 162 salinity samples is 2.797 ppt and therefore the E. coli water quality objective is not applicable for water contact recreation beneficial use support determination in this waterbody. Therefore, this waterbody is being considered for removal from the CWA section 303(d) List under section 4 of the Listing Policy due to a change in water quality standards.

After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the CWA section 303(d) List because the E. coli bacteria water quality objective is not applicable.
 
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 CWA section 303(d) List because the water quality standard is not applicable for the pollutant, based on the salinity in this waterbody segment.
 
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 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 58895
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 15
Number of Exceedances: 2
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Two of the 15 samples exceeded theE. coli Objective of 235 MPN/100mL.
Data Reference: City of Watsonville Long Term Management Strategy Data, May 2009-Jul. 2010
 
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.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL. USEPA Ambient Water Quality Criteria for Bacteria -1986.
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Samples were collected at Watsonville Slough @ Ohlone Pkwy Bridge. CAR3051003019981209150043
Temporal Representation: Samples were collected monthly from May 2009 to July 2010.
Environmental Conditions:
QAPP Information: No QAPP provided with data. Data quality ok. City of Watsonville receiving waters.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 58896
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 64
Number of Exceedances: 18
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Eighteen of the 64 samples exceeded the E. coli objective of 235 MPN/100mL.
Data Reference: City of Watsonville Restoration Project Water Quality Data, Aug. 2004-Jun. 2010
 
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.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL. USEPA Ambient Water Quality Criteria for Bacteria -1986
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Samples were collected from the Manabe-Burgstrom Area. Site 1, Watsonville Slough at mid-point, south side of road/trail that crosses Watsonville Slough from Ford St., Site 2, Watsonville Slough about 30ft east of Ohlone Parkway and site 3, Watsonville Slough just east of Lee Rd. CAR3051003019981209150043
Temporal Representation: Samples were collected every monthly from May to August 2006 before the restoration and every two months from April 2007 to June 2010 after the restoration.
Environmental Conditions: Manabe-Burgstrom Area is a restoration site. Samples were collected pre-restoration in 2006 and post restoration in 2007-2010.
QAPP Information: No QAPP provided with data. Data quality ok. City of Watsonville receiving waters.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 58904
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 32
Number of Exceedances: 7
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Seven of the 32 samples exceeded the E. coli Objective of 235 MPN/100mL.
Data Reference: City of Watsonville Restoration Project Water Quality Data, Aug. 2004-Jun. 2010
 
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.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL. USEPA Ambient Water Quality Criteria for Bacteria -1986
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Samples were collected from site 2, Watsonville Slough at the tip of the peninsula about 300 ft E-NE of Nature Center. CAR3051003019981209150043
Temporal Representation: Samples were collected every two months from August 2004 to July 2005 before the restoration and every two months from October 2005 to June 2010 after the restoration.
Environmental Conditions: Upper Watsonville Slough is a restoration site. Samples were collected pre-restoration in 2004 and 2005 and post restoration in 2005-2010.
QAPP Information: No QAPP provided with data. Data quality ok. City of Watsonville receiving waters.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 150142
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 24
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Watsonville Slough to determine beneficial use support and the results are as follows: 6 of the 24 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
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 bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 305WSA
Temporal Representation: The samples were collected between the days 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 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 149837
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 6
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Watsonville Slough to determine beneficial use support and the results are as follows: 1 of the 6 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 305-WATSO-23
Temporal Representation: The samples were collected between the days of 2011-05-07 and 2016-05-07 .
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 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 149735
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Watsonville Slough to determine beneficial use support and the results are as follows: 1 of the 4 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 305-WATSO-22
Temporal Representation: The samples were collected between the days of 2011-05-07 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 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 149836
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Watsonville Slough to determine beneficial use support and the results are as follows: 0 of the 4 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 305-WATSO-21
Temporal Representation: The samples were collected between the days of 2011-05-07 and 2016-05-07 .
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 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 149878
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 6
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Watsonville Slough to determine beneficial use support and the results are as follows: 2 of the 6 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 305-BEACH-21
Temporal Representation: The samples were collected between the days of 2011-05-07 and 2016-05-07 .
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 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 18492
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 11
Number of Exceedances: 7
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Clean streams project) (R3_CLNStrm) data for Watsonville Slough to determine beneficial use support and results are as follows: 7 of 11 samples exceed the criterion for Escherichia coli.
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: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Watsonville Slough was collected at 2 monitoring sites [ 305-WATSO-23 - Watsonville Slough at Palm Beach Rd., 305-WATSO-21 - Watsonville Slough at Harkins Slough Road]
Temporal Representation: Data was collected over the time period 5/26/2004-11/8/2004.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: Regional Board approved QAPP. Data entry completed by volunteers. Multiple errors were identified in data and were flagged by RB staff (in communication with Clean Streams Program staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 11091
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 12
Number of Exceedances: 4
 
Data and Information Type: PATHOGEN 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: 4 of 12 samples exceed the criterion for Escherichia coli.
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: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 13639
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 57
Number of Exceedances: 32
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Watsonville Slough to determine beneficial use support and results are as follows: 32 of 57 samples exceed the criterion for Escherichia coli.
Data Reference: Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Watsonville Slough was collected at 5 monitoring sites [ Shell Rd at pump station, Pajaro Dunes Colony near confluence with Pajaro R, Lee Rd, San Andreas Rd, Harkins Slough Rd]
Temporal Representation: Data was collected over the time period 2/18/2003-12/9/2003.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 126061, Escherichia coli (E. coli)
Region 3     
Watsonville Slough
 
LOE ID: 18534
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 9
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Watsonville Slough to determine beneficial use support and results are as follows: 2 of 9 samples exceed the criterion for Escherichia coli.
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: USEPA Ambient Water Quality Criteria for Bacteria -1986.
Objective/Criterion Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Evaluation Guideline: Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15)
Guideline Reference: Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
 
Spatial Representation: Data for this line of evidence for Watsonville Slough was collected at 3 monitoring sites [ 305-WATSO-21 - Watsonville Slough at Harkins Slough Road, 305-WATSO-23 - Watsonville Slough at Palm Beach Rd., 305-WATSO-22 - Watsonville Slough at Pajaro Valley Water Management Agency Pump Station]
Temporal Representation: Data was collected over the time period 5/17/2003-5/7/2005. 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):
 
 
DECISION ID
131029
Region 3     
Watsonville Slough
 
Pollutant: Fecal Coliform
Final Listing Decision: Delist from 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (being addressed by USEPA approved TMDL)(2018)
Revision Status Revised
Reason for Delisting: Applicable WQS attained; due to change in WQS
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 pollutant is being considered for removal from the CWA section 303(d) List under section 4 of the Listing Policy due to a change in water quality standards.

The State Water Boards Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the ISWEBE Plan) contains two bacteria water quality objectives applicable to the REC-1 beneficial use which were adopted on August 7, 2018: where the salinity level of a waterbody is equal to or less than 1 part per thousand 95 percent or more of the time, the E. coli bacteria objective applies; and where the salinity level of a waterbody is greater than 1 part per thousand 95 percent or more of the time, the Enterococci bacteria objective applies.

These objectives supersede the fecal coliform water quality objective for water contact recreation. Consequently, the fecal coliform objective for water contact recreation is no longer applicable to this waterbody and those LOEs have been removed from this decision. Therefore, this waterbody is being removed from the CWA section 303(d) List under section 4 of the Listing Policy due to a change in water quality standards.

However, three lines of evidence (LOEs) are available in the administrative record to assess this pollutant and the non-contact recreation use. Therefore, this pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Eight of the 93 samples exceed the water quality objective for non-contact recreation.

After review of the available data and information for the non-contact recreation beneficial use, RWQCB staff concludes that the water body-pollutant combination should not be placed on the CWA section 303(d) List because applicable water quality standards for the pollutant are not being exceeded.

In accordance with section 2.2 of the Policy, there is sufficient justification to place it in the Being Addressed portion of the 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.

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. Eight of the 93 samples exceed the water quality objective for non-contact recreation, and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. The Watsonville Slough Pathogen TMDL has been approved by USEPA on 07/19/2007.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the CWA section 303(d) List under section 4 of the Listing Policy due to a change in water quality standards.

This water body pollutant combination should be placed in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.
 
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 131029, Fecal Coliform
Region 3     
Watsonville Slough
 
LOE ID: 14057
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 57
Number of Exceedances: 5
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Watsonville Slough to determine beneficial use support and results are as follows: 5 of 57 samples exceed the criterion for Coliform, Fecal.
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 non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml.
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 5 monitoring sites [ Shell Rd at pump station, Pajaro Dunes Colony near confluence with Pajaro R, Lee Rd, San Andreas Rd, Harkins Slough Rd]
Temporal Representation: Data was collected over the time period 2/18/2003-12/9/2003.
Environmental Conditions: Staff is not aware of any special conditions that might effect interpretation of the data.
QAPP Information: Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 131029, Fecal Coliform
Region 3     
Watsonville Slough
 
LOE ID: 11089
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 12
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN 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: 1 of 12 samples exceed the criterion for Coliform, Fecal.
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: The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml.
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 131029, Fecal Coliform
Region 3     
Watsonville Slough
 
LOE ID: 150093
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Non-Contact Recreation
 
Number of Samples: 24
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Watsonville Slough to determine beneficial use support and the results are as follows: 2 of the 24 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a 10% exceedance rate that is calculated for a 30-Day peroid.
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 Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section 3.3.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 mL, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 mL.
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(s), station(s): 305WSA
Temporal Representation: The samples were collected between the days 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
130179
Region 3     
Watsonville Slough
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: 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 removal from the section 303(d) List under sections 4.1 and 4.6 of the Listing Policy. Under 4.1 of the Policy, a minimum of one line of evidence is needed 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.

Seven lines of evidence are available in the administrative record to assess this pollutant.

Four LOEs summarize sediment samples. Seven of 17 sediment samples exceed the DDE evaluation guideline (MacDonald et al., 2000a) set to protect for aquatic life beneficial uses. These samples are associated with toxicity.

Based on the readily available data and information, the weight of evidence indicates that the water body-pollutant combination should not be removed from the section 303(d) List because applicable water quality standards for the pollutant are 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. Seven of 17 sediment samples exceed the evaluation guidelines and these samples are associated with sediment toxicity. This exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) List because applicable water quality standards for the pollutant are 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 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 58873
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 1
 
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 2 samples exceed the criterion for DDE. 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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDE is 31.3 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 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 58991
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Nine samples were collected at three different stations to evaluate sediment toxicity. Seven of the nine samples exhibited significant toxicity. The toxicity tests included survival and growth of Hyalella azteca. Statistically significant effects on Hyalella azteca survival were observed at 305WAB (7/2/08).
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 that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Toxicity was defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. The t-test is used to determine if there is a statistically significant decrease in organism response in the sample as compared to the control. In the SWAMP data format, a Significance Effect Code of SL denotes toxic test results.
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
 
Spatial Representation: The samples were collected at station 305WAB - Watsonville Slough below Beach Street Input.
Temporal Representation: The samples were collected in May, July and October 2008 and October 2009.
Environmental Conditions:
QAPP Information: The data was collected for the Watershed-scale Evaluation of Agricultural BMP Effectiveness Protecting Critical Coastal Habitats project. A QAPP was provided and the data was analyzed at the Marine Pollution Studies Laboratory and submitted in SWAMP format.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 58843
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Three samples were collected to evaluate sediment toxicity. Two of the three samples exhibited significant toxicity to Hyalella azteca. The toxicity tests included growth and survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. It should be noted that the samples collected in 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
 
Spatial Representation: The samples were collected at 305WSA-Watsonville Slough at San Andreas Road.
Temporal Representation: The samples were collected annually from April 2007 to April 2009.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
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 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 153317
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
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 1 samples exceeded the evaluation guideline for DDE (Dichlorodiphenyldichloroethylene) .
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 DDE from MacDonald et al., 2000a which states that the probable effect concentration for Sum DDE is 31.3 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 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 94050
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 4
 
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: 4 of 11 samples exceed the criterion for DDE.
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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDE is 31.3 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 3 monitoring sites [ Pajaro River Estuary-Sediment site 3 - 305PJESD3, Pajaro River Estuary-Sediment site 4 - 305PJESD4, 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): Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.
 
Line of Evidence (LOE) for Decision ID 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 148806
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 4 of the 4 samples collected by RWB3 Cooperative Monitoring Program for Watsonville Slough exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca, for Survival, Hyalella azteca, for Growth (wt/surv indiv)
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 (Central Coastal Basin Plan 2019).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 station. Monitoring site: ( 305WSA )
Temporal Representation: The samples were collected between the dates of 2015-04-22 and 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 130179, DDE (Dichlorodiphenyldichloroethylene)
Region 3     
Watsonville Slough
 
LOE ID: 58870
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
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 3 samples exceed the criterion for DDE.
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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDE is 31.3 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.
 
 
DECISION ID
107176
Region 3     
Watsonville Slough
 
Pollutant: Malathion
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: A Source Unknown
Expected TMDL Completion Date: 2035
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Three lines of evidence are available in the administrative record to assess this pollutant. For lines of evidence where the fraction is “not recorded” or "none" staff assumed that the fraction is “total” and the sample and exceedance counts are summed for the purpose of making this decision.

Two of 11 samples exceed the evaluation guideline applied to protect aquatic life beneficial uses (Faria et al., 2010). 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".

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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 11 water samples exceed the aquatic life evaluation guideline and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) List because applicable water quality standards for the pollutant are 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 107176, Malathion
Region 3     
Watsonville Slough
 
LOE ID: 94178
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 2
 
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: 2 of 9 samples exceed the criterion for MALATHION.
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 Malathion does not exceed 0.028 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 107176, Malathion
Region 3     
Watsonville Slough
 
LOE ID: 168560
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
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 Malathion. 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: 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 four-day average concentration of malathion does not exceed 0.028 ug/L more than once every three years on the average (Faria et al., 2010).
Guideline Reference: Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
 
Spatial Representation: The samples were collected at 1 monitoring site (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): 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 107176, Malathion
Region 3     
Watsonville Slough
 
LOE ID: 168591
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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: 0 of 1 samples exceeded the water quality threshold for Malathion.
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 four-day average concentration of malathion does not exceed 0.028 ug/L more than once every three years on the average (Faria et al., 2010).
Guideline Reference: Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
 
Spatial Representation: The samples were collected at 1 monitoring site (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): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
107193
Region 3     
Watsonville Slough
 
Pollutant: Toxicity
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: 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 removal from the section 303(d) List under sections 4.1 and 4.6 of the Listing Policy. Under 4.1 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Sixteen lines of evidence are available in the administrative record to assess this pollutant. One sample can have multiple toxicity test results (or endpoints) but will be counted only once. One sample is defined as being collected on the same day at the same location.

Ten LOEs summarize water samples. Eight out of 37 samples were toxic to test organisms (exhibited a significant increase in mortality, decrease in cell density, decrease in growth or reproduction compared to the laboratory control) and therefore exceeded the narrative general water quality objective for toxicity, set to protect for aquatic life beneficial uses.

Six LOEs summarize sediment samples. Eight out of 12 samples were toxic to test organisms (exhibited a significant increase in mortality, decrease in cell density, decrease in growth or reproduction compared to the laboratory control) and therefore exceeded the narrative general water quality objective for toxicity, set to protect for aquatic life beneficial uses.

Based on the readily available data and information, the weight of evidence indicates that the water body-pollutant combination should not be removed from the section 303(d) List because applicable water quality standards for the pollutant are 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. Eight out of 37 water samples, and eight out of 12 sediment samples, were toxic to test organisms relative to the control and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) List because applicable water quality standards for the pollutant are 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 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24714
 
Pollutant: Plant Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Toxicity, Selenastrum capricornutum Growth (Cell Density) 4 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction in cell count of test organism relative to the control (alpha < 0.05) and cell count <80% of control.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24691
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
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 3 samples exceed the criterion for Toxicity, Ceriodaphnia dubia Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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: 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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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 2/21/2006-8/22/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24695
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Toxicity, Ceriodaphnia dubia Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24701
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
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 1 samples exceed the criterion for Toxicity, Hyalella azteca Survival (%) 10 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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: 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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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 on a single day 5/19/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24702
 
Pollutant: Invertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 1 samples exceed the criterion for Toxicity, Hyalella azteca Survival (%) 10 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24713
 
Pollutant: Plant Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
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 3 samples exceed the criterion for Toxicity, Selenastrum capricornutum Growth (Cell Density) 4 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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: 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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction in cell count of test organism relative to the control (alpha < 0.05) and cell count <80% of control.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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 2/21/2006-9/26/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 58991
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 1
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Nine samples were collected at three different stations to evaluate sediment toxicity. Seven of the nine samples exhibited significant toxicity. The toxicity tests included survival and growth of Hyalella azteca. Statistically significant effects on Hyalella azteca survival were observed at 305WAB (7/2/08).
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 that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Toxicity was defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. The t-test is used to determine if there is a statistically significant decrease in organism response in the sample as compared to the control. In the SWAMP data format, a Significance Effect Code of SL denotes toxic test results.
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
 
Spatial Representation: The samples were collected at station 305WAB - Watsonville Slough below Beach Street Input.
Temporal Representation: The samples were collected in May, July and October 2008 and October 2009.
Environmental Conditions:
QAPP Information: The data was collected for the Watershed-scale Evaluation of Agricultural BMP Effectiveness Protecting Critical Coastal Habitats project. A QAPP was provided and the data was analyzed at the Marine Pollution Studies Laboratory and submitted in SWAMP format.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 58843
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Three samples were collected to evaluate sediment toxicity. Two of the three samples exhibited significant toxicity to Hyalella azteca. The toxicity tests included growth and survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. It should be noted that the samples collected in 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
 
Spatial Representation: The samples were collected at 305WSA-Watsonville Slough at San Andreas Road.
Temporal Representation: The samples were collected annually from April 2007 to April 2009.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
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 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 148807
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 4 of the 4 samples collected by RWB3 Cooperative Monitoring Program for Watsonville Slough exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca, for Survival, Hyalella azteca, for Growth (wt/surv indiv)
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 (Central Coastal Basin Plan 2019).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 station. Monitoring site: ( 305WSA )
Temporal Representation: The samples were collected between the dates of 2015-04-22 and 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 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 149059
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 12
Number of Exceedances: 3
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 3 of the 12 samples collected by RWB3 Cooperative Monitoring Program for Watsonville Slough exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Chironomus dilutus, for Survival, Selenastrum capricornutum, for Total Cell Count, Thalassiosira pseudonana, for Total Cell Count, Cyprinodon variegatus, for Survival, Ceriodaphnia dubia, for Young/female, Pimephales promelas, for Survival, Ceriodaphnia dubia, for Survival, Hyalella azteca, for Survival, Cyprinodon variegatus, for Biomass (wt/orig indiv), Pimephales promelas, for Biomass (wt/orig indiv)
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
Guideline Reference: SWAMP_Memo_Toxicity_Data_Intrepretation
 
Spatial Representation: The samples were collected at 1 station. Monitoring site: ( 305WSA )
Temporal Representation: The samples were collected between the dates of 2013-03-28 and 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 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 149043
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 3
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 3 of the 12 samples collected by RWB3 Cooperative Monitoring Program for Watsonville Slough exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Chironomus dilutus, for Survival, Selenastrum capricornutum, for Total Cell Count, Thalassiosira pseudonana, for Total Cell Count, Cyprinodon variegatus, for Survival, Ceriodaphnia dubia, for Young/female, Pimephales promelas, for Survival, Ceriodaphnia dubia, for Survival, Hyalella azteca, for Survival, Cyprinodon variegatus, for Biomass (wt/orig indiv), Pimephales promelas, for Biomass (wt/orig indiv)
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
Guideline Reference: SWAMP_Memo_Toxicity_Data_Intrepretation
 
Spatial Representation: The samples were collected at 1 station. Monitoring site: ( 305WSA )
Temporal Representation: The samples were collected between the dates of 2013-03-28 and 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 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24708
 
Pollutant: Vertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
Data and Information Type: TOXICITY TESTING
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 3 samples exceed the criterion for Toxicity, Pimephales promelas Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
Data Reference: Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data
  Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data
 
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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 2/21/2006-9/26/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 24709
 
Pollutant: Vertebrate Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed CCAMP_SWAMP Monitoring (04SW3001) data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 2 samples exceed the criterion for Toxicity, Pimephales promelas Survival (%) 7 days. Toxicity is defined by SWAMP (2004) as follows: Significant toxicity in the survival endpoint when compared to the negative control based on a statistical test with alpha of less than 5%, and less than the evaluation threshold (both criteria are met).
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. Compliance with this objective will be determined by use of indicator organisms, analyses of species diversity, population density, growth anomalies, toxicity bioassays of appropriate duration, or other appropriate methods as specified by the Regional Board (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)
 
Evaluation Guideline: Significant reduction of survival of test organism relative to the control (alpha < 0.05) and test organism survival is 20% less than the control survival.
Guideline Reference: Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 148806
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 4
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: 4 of the 4 samples collected by RWB3 Cooperative Monitoring Program for Watsonville Slough exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca, for Survival, Hyalella azteca, for Growth (wt/surv indiv)
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 (Central Coastal Basin Plan 2019).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 station. Monitoring site: ( 305WSA )
Temporal Representation: The samples were collected between the dates of 2015-04-22 and 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 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 58992
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Nine samples were collected to evaluate water toxicity. Two of the ten samples exhibited significant toxicity.
Three samples were tested using Hyalella azteca only, six samples were tested using Ceriodaphnia dubia only and one sample (collected on 10/14/09) was tested using two organisms, Hyalella azteca and Ceriodaphnia dubia. Statistically significant effects to Ceriodaphnia dubia were reported for the samples collected in February and October 2009. The October 2009 sample was also toxic to Hyalella azteca.
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 that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Toxicity was defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. The t-test is used to determine if there is a statistically significant decrease in organism response in the sample as compared to the control. In the SWAMP data format, a Significance Effect Code of SL denotes toxic test results.
Guideline Reference: Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012
Guideline Reference: Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013
 
Spatial Representation: The samples were collected at 305WAB (AKA 305WAT) -Watsonville Slough below Beach Street Input. This location has two different station codes in this data set.
Temporal Representation: The samples ere collected from January 2008 to October 2009.
Environmental Conditions:
QAPP Information: The data was collected for the Watershed-scale Evaluation of Agricultural BMP Effectiveness Protecting Critical Coastal Habitats project. A QAPP was provided and the data was analyzed at the Marine Pollution Studies Laboratory and submitted in SWAMP format.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107193, Toxicity
Region 3     
Watsonville Slough
 
LOE ID: 58990
 
Pollutant: Toxicity
LOE Subgroup: Toxicity
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 2
 
Data and Information Type: TOXICITY TESTING
Data Used to Assess Water Quality: Eleven samples were collected to evaluate water toxicity. Two of the eleven samples exhibited significant toxicity. The toxicity tests for the samples included survival and reproduction of Ceriodaphnia dubia, survival and growth of Pimephales promelas and total cell count (growth) of Selenastrum capricornutum. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location. The sample collected on 10/1/2008 exhibited significant toxicity to Ceriodaphnia dubia reproduction. The sample collected on 1/19/10 exhibited significant toxicity to Pimephales promelas growth. It should be noted that the samples collected in 2006, in the data file associated with this LOE, are not included in this LOE because they were included in the previous assessment cycle.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Significant effect is defined here using a two-tier approach consistent with the method used by the SWAMP program. The effect must be significant when compared to the control sample based on statistical test alpha level of 0.05 (Probability field in data set) AND the mean must be more than 20 percent different from the control (PercentControl field in data set).
Guideline Reference: Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013
Guideline Reference: Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. EPA-821-R-02-012
 
Spatial Representation: The samples were collected at 305WSA-Watsonville Slough at San Andreas Road.
Temporal Representation: The samples were collected from October 2007 to March 2010.
Environmental Conditions:
QAPP Information: The data was collected for the CCRWQCB Cooperative Monitoring Program for Agriculture data and provided in SWAMP format. QAPP for the Cooperative Monitoring program for Agriculture in Region 3.
QAPP Information Reference(s): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
DECISION ID
107195
Region 3     
Watsonville Slough
 
Pollutant: Turbidity
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 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 removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Eight lines of evidence are available in the administrative record to assess this pollutant. A total of 236 of the 364 samples exceed the evaluation guideline (Shoup, D.E. and Wahl D.H., 2009), used to interpret the water quality objective for turbidity.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. A total of 236 of the 364 samples exceed the evaluation guideline and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are 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 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 182287
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 55
Number of Exceedances: 26
 
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: 26 of 55 samples exceeded the water quality threshold for Turbidity.
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: Waters shall be free of changes in turbidity that cause nuisance or 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: Turbidities of 40 NTU or greater can cause a reduced foraging efficiency and a shift in prey selection in piscivorous fish (largemouth bass) due to interference with their ability to find prey (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
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 2018-12-19
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 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 183168
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
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: 1 of 1 samples exceeded the water quality threshold for Turbidity.
Data Reference: Field, Habitat data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or 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: Turbidities of 40 NTU or greater can cause a reduced foraging efficiency and a shift in prey selection in piscivorous fish (largemouth bass) due to interference with their ability to find prey (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
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: Central Coast Wetlands Group at Moss Landing Marine Labs. 2014. 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 .
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 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 182308
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 10
 
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: 10 of 24 samples exceeded the water quality threshold for Turbidity.
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 be free of changes in turbidity that cause nuisance or 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: Turbidities of 40 NTU or greater can cause a reduced foraging efficiency and a shift in prey selection in piscivorous fish (largemouth bass) due to interference with their ability to find prey (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
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 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 48861
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 22
Number of Exceedances: 8
 
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: 8 of 22 samples exceed the criterion for Turbidity(NTU).
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Turbidities of 40 NTU or greater can cause a reduction in piscivorous fish (largemouth bass) growth due to interference with their ability to find food (Shoup, D.E. and Wahl D.H., 2009).
Guideline Reference: The Effects of Turbidity on Prey Selection by Piscivorous Largemouth Bass
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
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 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 13698
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 93
Number of Exceedances: 39
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Watsonville Slough to determine beneficial use support and results are as follows: 39 of 93 samples exceed the criterion for Turbidity(NTU).
Data Reference: Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. 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)
 
Evaluation Guideline: Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
Spatial Representation: Data for this line of evidence for Watsonville Slough was collected at 6 monitoring sites [ Shell Rd at pump station, Lee Rd, San Andreas Rd, Pajaro Dunes Colony near confluence with Pajaro R, Errington 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: Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 17542
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 156
Number of Exceedances: 143
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for Watsonville Slough to determine beneficial use support and results are as follows: 143 of 156 samples exceed the criterion for Turbidity(NTU).
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: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. 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)
 
Evaluation Guideline: Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
Spatial Representation: Data for this line of evidence for Watsonville Slough was collected at 5 monitoring sites [ WS-LEE - Watsonville Slough at Lee, WS-SAR - Watsonville Slough at San Andreas Road, WS-SHB - Watsonville Slough below Shell Road, WS-SHA - Watsonville Slough above Shell Road, WS-ERR - Watsonville Slough at Errington]
Temporal Representation: Data was collected over the time period 9/21/2005-2/6/2007.
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 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 13727
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 3
 
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: 3 of 5 samples exceed the criterion for Turbidity(NTU).
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: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. 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)
 
Evaluation Guideline: Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
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 2/21/2006-9/26/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107195, Turbidity
Region 3     
Watsonville Slough
 
LOE ID: 12021
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 6
 
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: 6 of 8 samples exceed the criterion for Turbidity(NTU).
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: Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses. 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)
 
Evaluation Guideline: Sigler et al. (1984) states that turbidities of 25 NTU's or greater caused reduction in juvenile salmonid growth due to interference with their ability to find food.
Guideline Reference: Effects of chronic turbidity on density and growth of steelheads and coho salmon. Transactions of the American Fisheries Society 113:142-150
 
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 7/21/2005-3/16/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
 
DECISION ID
128275
Region 3     
Watsonville Slough
 
Pollutant: Nitrate
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: Agriculture | Domestic Animals/Livestock | Natural Sources | Urban Runoff/Storm Sewers
TMDL Name: Pajaro River Watershed Nutrients
TMDL Project Code: 999
Expected TMDL Completion Date: 2018
Date TMDL Approved by USEPA: 10/06/2016
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under section 4.1 a single line of evidence is necessary to assess listing status.

Ten lines of evidence are available in the administrative record to assess this pollutant. Where the fraction is none, not recorded, or total, staff assumed that the fraction is dissolved, based on the analytical method. In these cases, sample and exceedance counts are summed for the purpose of making this decision.

The Aquatic Life beneficial uses are not supported. Since the 2010 Integrated Report assessment cycle, Central Coast Water Board staff assessed nitrate data using an evaluation guideline (Central Coast Region Technical Report, 2010) used to interpret the narrative water quality objective for biostimulatory substances, set to protect Cold and Warm Freshwater Habitat beneficial uses. Thirty-two of the 45 nitrate samples and 60 of the 85 nitrate/nitrite samples exceed this evaluation guideline. In addition, and in accordance with section 4.11 of the Listing Policy, the following evidence supports the conclusion that nitrate contributes to or causes a bio-stimulatory response in this waterbody.


1. Dissolved oxygen for this water body ranged from under 1.0 mg/L to over 12.0 mg/L, frequently exceeding (falling below) the Warm Freshwater Habitat objective of 5.0 mg/L. The dissolved oxygen upper screening level of 13.0 mg/L (R3 NNE Technical Report, 2010) was not exceeded but there is ample evidence of wide fluctuations in daily dissolved oxygen concentrations. This water body segment is on the CWA section 303(d) List for low dissolved oxygen.
2. The percent cover of floating algal mats ranged from 0-80% in the creek, at times exceeding the screening threshold of 50% (R3 NNE Technical Report, 2010). In stream aquatic vegetation was at times more than 90% cover.
3. Water column chlorophyll a concentrations ranged from 0 to over 200 ug/L, frequently exceeding the screening threshold of 15 ug/L (R3 NNE Technical Report, 2010). However, the evaluation guideline used in the 303(d) assessment (40 ug/L) is not being exceeded at a frequency that would result in placement of this water segment-pollutant combination on the CWA section 303(d) List for chlorophyll a.
4. Using site-specific data from this water body, the California Benthic Biomass Predictor Tool, v. 13 (Tetratech, 2007) predicted a benthic algal contribution to oxygen deficit for this water body ranging 2.42 mg/L. This exceeds the screening threshold for benthic algal contribution to oxygen deficit of 1.25 mg/L (R3 NNE Technical Report, 2010).
5. Using site-specific data from this water body, the California Benthic Biomass Predictor Tool, v. 13 (Tetratech, 2007) predicted algae biomass concentrations ranging from 56 to 141 mg/m2. This exceeds the California¿s Nutrient Numeric Endpoint (Creager, et al., 2006) warm water threshold values of 80 grams/m2 ash-free dry weight (AFDW) for algal density.
6. Using site-specific data from this water body, the California Benthic Biomass Predictor Tool, v. 13 (Tetratech, 2007) predicted benthic chlorophyll a concentrations of 141 mg/m2. This do not exceed the California¿s Nutrient Numeric Endpoint (Creager, et al., 2006) warm water threshold values of 200 mg/m2 benthic chlorophyll a.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Thirty-two of the 45 nitrate samples and 60 of the 85 nitrate/nitrite samples exceed the evaluation guideline for maximum nitrate concentration (R3 NNE Technical Report, 2010) and the protection of aquatic life uses from bio-stimulatory or eutrophic effects and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. In addition, and in accordance with section 4.11 of the Listing Policy, there is supporting evidence which indicates existence of, and high risk for, eutrophication. Furthermore, this water body segment is on the 303(d) List due to low dissolved oxygen conditions.
4. The Pajaro River Watershed Nutrients TMDL has been approved by USEPA.
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation: 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. Thirty-two of the 45 nitrate samples and 60 of the 85 nitrate/nitrite samples exceed the evaluation guideline for maximum nitrate concentration (R3 NNE Technical Report, 2010) and the protection of aquatic life uses from bio-stimulatory or eutrophic effects and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. In addition, and in accordance with section 4.11 of the Listing Policy, there is supporting evidence which indicates existence of, and high risk for, eutrophication. Furthermore, this water body segment is on the 303(d) List due to low dissolved oxygen conditions.
4. The Pajaro River Watershed Nutrients TMDL has been approved by USEPA.
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 172202
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 3
 
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: 3 of 4 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: The samples were collected at 1 monitoring site (305-WATSO-22)
Temporal Representation: The samples were collected between the dates of 2011-05-07 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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 173027
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 6
 
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: 6 of 6 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: The samples were collected at 1 monitoring site (305-WATSO-23)
Temporal Representation: The samples were collected between the dates of 2011-05-07 and 2016-05-07
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 172047
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
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 5 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: The samples were collected at 1 monitoring site (305-WATSO-21)
Temporal Representation: The samples were collected between the dates of 2011-05-07 and 2016-05-07
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 173563
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 17
 
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: 17 of 24 samples exceeded the water quality threshold for Nitrate as N.
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 biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 172035
 
Pollutant: Nitrogen, Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 6
 
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: 6 of 6 samples exceeded the water quality threshold for Nitrate as N.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: The samples were collected at 1 monitoring site (305-BEACH-21)
Temporal Representation: The samples were collected between the dates of 2011-05-07 and 2016-05-07
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 171550
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 56
Number of Exceedances: 39
 
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: 39 of 56 samples exceeded the water quality threshold for Nitrate + Nitrite as N.
Data Reference: Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 149452
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
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: 1 of 1 samples exceeded the water quality standard for Nitrate + Nitrite as N.
Data Reference: CMP water quality data 10/17/2018--12/20/2018.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 171683
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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: 0 of 1 samples exceeded the water quality threshold for Nitrate + Nitrite as N.
Data Reference: Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
Spatial Representation: The samples were collected at 1 monitoring site (305WSA)
Temporal Representation: The samples were collected between the dates of 2010-08-24 and 2010-08-24
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 48894
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 11
 
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: 11 of 15 samples exceed the criterion for Nitrate/Nitrite as N.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Technical Approach to Develop Nutrient Numeric Endpoints for California. U.S. EPA Region IX. State Water Resources Control Board. 68-C-02-108-To-111
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
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 4/27/2009-6/29/2010.
Environmental Conditions: Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.
QAPP Information: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
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 128275, Nitrate
Region 3     
Watsonville Slough
 
LOE ID: 171618
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 9
 
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: 9 of 12 samples exceeded the water quality threshold for Nitrate + Nitrite as N.
Data Reference: Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or 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: Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N.
Guideline Reference: Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints.
 
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 2011-12-12
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
107185
Region 3     
Watsonville Slough
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: Agriculture | Domestic Animals/Livestock | Natural Sources | Urban Runoff/Storm Sewers
TMDL Name: Pajaro River Watershed Nutrients
TMDL Project Code: 999
Expected TMDL Completion Date: 2018
Date TMDL Approved by USEPA: 10/06/2016
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal from the section 303(d) List under sections 2.2 and 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Thirty-five lines of evidence are available in the administrative record to assess this pollutant.

Eighty-one of 116 samples exceed the water quality objective for fish spawning (Basin Plan). Four hundred forty of 1,102 samples exceed the water quality objective for warm freshwater habitat (Basin Plan). Sixty-one of 116 samples exceed the water quality objective for estuarine habitat (Basin Plan). Note that there is no difference between samples fractions ‘dissolved’ and ‘total,’ therefore sample and exceedance counts will be summed for the purpose of this decision.

Previous decisions (pre-2020) included dissolved oxygen saturation LOEs as ancillary evidence. This decision will no longer include dissolved oxygen saturation and these LOEs will be retired next cycle.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. Eighty-one of 116 samples exceed the fish spawning objective; 440 of 1,102 samples exceed the warm freshwater habitat objective; and 61 of 116 exceed the estuarine habitat objective. These exceed the allowable frequency listed in Table 4.2 of the Listing Policy.
4. The Pajaro River watershed nutrient TMDL was approved by USEPA on October 6, 2016.
5. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) List because applicable water quality standards for the pollutant are being exceeded.

Furthermore, this pollutant waterbody combination should be placed in the 'Being Addressed' portion of the 303(d) List because a TMDL has been completed and approved by RWQCB and USEPA, and is expected to result in attainment of the standard.
 
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 48185
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Fish Spawning
 
Number of Samples: 7
Number of Exceedances: 1
 
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: 1 of 7 samples exceed the criterion for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (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: A QAPP was not specifically written for this project. However, staff conducting data collection and laboratory analysis are also SWAMP contractors. All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 48896
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Fish Spawning
 
Number of Samples: 21
Number of Exceedances: 21
 
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: 21 of 21 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 17855
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 868
Number of Exceedances: 324
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Monterey Area Research Consortium (R3_MARC) data for Watsonville Slough to determine beneficial use support and results are as follows: 324 of 868 samples exceed the criterion for Oxygen, Dissolved.
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 8 monitoring sites [ WS-LEE - Watsonville Slough at Lee, WS-SAR - Watsonville Slough at San Andreas Road, WS-SHA - Watsonville Slough above Shell Road, WS-SHB - Watsonville Slough below Shell Road, WS-ERR - Watsonville Slough at Errington, Krausse confluence, Krausse ditch w/ willows, Krausse open water]
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 13690
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 3
 
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: 3 of 5 samples exceed the criterion for Oxygen, Dissolved.
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 2/21/2006-9/26/2006. 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 58962
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 34
Number of Exceedances: 16
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Sixteen 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 dissolved oxygen content of all surface waters designated as "Warm Freshwater Habitat" must be greater than 5.0 mg/L.
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: Data were collected by the City of Watsonville staff for the Manabe-Burgstrom Area 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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 48186
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 7
Number of Exceedances: 1
 
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: 1 of 7 samples exceed the criterion for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (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: A QAPP was not specifically written for this project. However, staff conducting data collection and laboratory analysis are also SWAMP contractors. All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 18155
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 41
Number of Exceedances: 27
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Clean streams project) (R3_CLNStrm) data for Watsonville Slough to determine beneficial use support and results are as follows: 27 of 41 samples exceed the criterion for Oxygen, Dissolved.
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 3 monitoring sites [ 305-WATSO-23 - Watsonville Slough at Palm Beach Rd., 305-WATSO-21 - Watsonville Slough at Harkins Slough Road, 305-WATSO-22 - Watsonville Slough at Pajaro Valley Water Management Agency Pump Station]
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: Regional Board approved QAPP. Data entry completed by volunteers. Multiple errors were identified in data and were flagged by RB staff (in communication with Clean Streams Program staff) prior to assessment of data.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 58961
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Two 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 dissolved oxygen content of all surface waters designated as "Warm Freshwater Habitat" must be greater than 5.0 mg/L.
Objective/Criterion Reference: Water Quality Control Plan for the Central Coastal Basin
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from Salsipuedes Creek at E Lake Ave Bridge.
Temporal Representation: Samples were collected approximately once a month from May 2009 to July 2010.
Environmental Conditions:
QAPP Information: Data were collected by the City of Watsonville staff for local watershed monitoring purposes. 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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 48906
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 21
Number of Exceedances: 20
 
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: 20 of 21 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 18120
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Central Coast Regional Board Staff assessed Coastal Watershed Council (Snapshot day monitoring) (R3_Snap) data for Watsonville Slough to determine beneficial use support and results are as follows: 3 of 11 samples exceed the criterion for Oxygen, Dissolved.
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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 3 monitoring sites [ 305-WATSO-21 - Watsonville Slough at Harkins Slough Road, 305-WATSO-23 - Watsonville Slough at Palm Beach Rd., 305-WATSO-22 - Watsonville Slough at Pajaro Valley Water Management Agency Pump Station]
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 12019
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Warm Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 5
 
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: 5 of 12 samples exceed the criterion for Oxygen, Dissolved.
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, dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time.
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174406
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 59
Number of Exceedances: 32
 
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: 32 of 59 samples exceeded the water quality threshold for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 2018-12-19
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174602
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 24
Number of Exceedances: 7
 
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: 7 of 24 samples exceeded the water quality threshold for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 2017-12-05
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174370
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174374
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174567
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175232
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174700
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175797
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174442
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 59
Number of Exceedances: 32
 
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: 32 of 59 samples exceeded the water quality threshold for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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 2018-12-19
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175182
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174540
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175796
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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: Central Coast Wetlands Group at Moss Landing Marine Labs. 2014. 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 .
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 48184
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 7
Number of Exceedances: 1
 
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: 1 of 7 samples exceed the criterion for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (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: A QAPP was not specifically written for this project. However, staff conducting data collection and laboratory analysis are also SWAMP contractors. All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 48895
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 21
Number of Exceedances: 21
 
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: 21 of 21 samples exceed the criterion for Oxygen, Dissolved.
Data Reference: Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174402
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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: Central Coast Wetlands Group at Moss Landing Marine Labs. 2014. 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 .
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175170
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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: Central Coast Wetlands Group at Moss Landing Marine Labs. 2014. 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 .
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174323
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174527
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175229
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 59
Number of Exceedances: 45
 
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: 45 of 59 samples exceeded the water quality threshold for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 2018-12-19
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174551
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174431
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 24
Number of Exceedances: 14
 
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: 14 of 24 samples exceeded the water quality threshold for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 7.0 mg/l at any time (Water Quality Control Plan, Central Coast Basin).
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 2017-12-05
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 175196
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Oxygen, Dissolved.
Data Reference: Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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 107185, Oxygen, Dissolved
Region 3     
Watsonville Slough
 
LOE ID: 174401
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 24
Number of Exceedances: 7
 
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: 7 of 24 samples exceeded the water quality threshold for Oxygen, Dissolved.
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 dissolved oxygen concentration shall not be reduced below 5.0 mg/L at any time for waters not mentioned by a specific beneficial use (Water Quality Control Plan, Central Coast Basin).
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 2017-12-05
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
107177
Region 3     
Watsonville Slough
 
Pollutant: 2,4,6-Trichlorophenol
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 107177, 2,4,6-Trichlorophenol
Region 3     
Watsonville Slough
 
LOE ID: 183386
 
Pollutant: 2,4,6-Trichlorophenol
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 0 of 3 samples exceeded the water quality threshold for Trichlorophenol, 2,4,6-.
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 6.5 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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
107180
Region 3     
Watsonville Slough
 
Pollutant: 2,4-Dichlorophenol
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 107180, 2,4-Dichlorophenol
Region 3     
Watsonville Slough
 
LOE ID: 163832
 
Pollutant: 2,4-Dichlorophenol
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 2
Number of Exceedances: 0
 
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: 0 of 2 samples exceeded the water quality threshold for Dichlorophenol, 2,4-.
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 790 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (305WSA)
Temporal Representation: The samples were collected between the dates of 2017-04-27 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
107181
Region 3     
Watsonville Slough
 
Pollutant: 2,4-Dimethylphenol
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 107181, 2,4-Dimethylphenol
Region 3     
Watsonville Slough
 
LOE ID: 164621
 
Pollutant: 2,4-Dimethylphenol
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 0 of 3 samples exceeded the water quality threshold for Dimethylphenol, 2,4-.
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 2,300 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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
107183
Region 3     
Watsonville Slough
 
Pollutant: 2,4-Dinitrophenol
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 107183, 2,4-Dinitrophenol
Region 3     
Watsonville Slough
 
LOE ID: 165056
 
Pollutant: 2,4-Dinitrophenol
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 1
Number of Exceedances: 0
 
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: 0 of 1 samples exceeded the water quality threshold for Dinitrophenol, 2,4-.
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 14,000 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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
107189
Region 3     
Watsonville Slough
 
Pollutant: 2-Chlorophenol
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 107189, 2-Chlorophenol
Region 3     
Watsonville Slough
 
LOE ID: 160981
 
Pollutant: 2-Chlorophenol
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 0 of 3 samples exceeded the water quality threshold for Chlorophenol, 2-.
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 400 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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
129878
Region 3     
Watsonville Slough
 
Pollutant: Alachlor
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 94159 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks.

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'.

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 129878, Alachlor
Region 3     
Watsonville Slough
 
LOE ID: 225124
 
Pollutant: Alachlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: 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 Alachlor.
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 Alachlor is the USEPA Aquatic Life Benchmark of 1.64 ug/L for a nonvascular plant (acute).
Guideline Reference: OPP Aquatic Life Benchmarks
 
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
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: 157144
 
Pollutant: Aldicarb
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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: OPP Aquatic Life Benchmarks
 
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 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: 0
Number of Exceedances: 0
 
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: OPP Aquatic Life Benchmarks
 
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): Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6
 
 
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: 58978
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 64
Number of Exceedances: 1
 
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: 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 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: Data were collected by the City of Watsonville staff for the Manabe-Burgstrom Area 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: 58976
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 14
Number of Exceedances: 0
 
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: Data were collected by the City of Watsonville staff for local watershed monitoring purposes. 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: 48892
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 0
 
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: 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 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). All data are flagged as appropriate.
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: 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: 12
Number of Exceedances: 0
 
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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the SWAMP QAMP, (Puckett, 2002). QA data are included in submission. All data are flagged as appropriate.
QAPP Information Reference(s):
 
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: 2
Number of Exceedances: 0
 
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: 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 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: All data was collected following the Standard Operating Procedures and Data Quality Objectives outlined in the Cooperative Monitoring Program QAPP, (Clark and Ogle 2006). QA data are included in submission. All data are flagged as appropriate.
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: 32
Number of Exceedances: 1
 
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: 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: 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: 183823
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 1
 
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: 219288
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 44
Number of Exceedances: 1
 
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: 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: 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: 219314
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 16
Number of Exceedances: 1
 
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: 149451
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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: 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: 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: 58977
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 33
Number of Exceedances: 0
 
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: 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 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):
 
 
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: 8
Number of Exceedances: 0
 
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: OPP Aquatic Life Benchmarks
 
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 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: 2
Number of Exceedances: 0
 
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: 0 of 2 samples exceeded the water quality threshold for Atrazine.
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: OPP Aquatic Life Benchmarks
 
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
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: 2
Number of Exceedances: 0
 
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: 0 of 2 samples exceeded the water quality threshold for Azinphos Methyl.
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: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
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: 3
Number of Exceedances: 0
 
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 Bensulide.
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: OPP Aquatic Life Benchmarks
 
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
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: 9
Number of Exceedances: 0
 
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: 9
Number of Exceedances: 0
 
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: 3
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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: 9
Number of Exceedances: 0
 
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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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 3 monitoring sites [ Pajaro River Estuary-Sediment site 3 - 305PJESD3, Pajaro River Estuary-Sediment site 4 - 305PJESD4, 305WAT-Watsonville Slough below Beach Street Input - 305WAB]
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: 151620
 
Pollutant: Bifenthrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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
 
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: 3
Number of Exceedances: 1
 
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
 
 
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: 8
Number of Exceedances: 0
 
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: OPP Aquatic Life Benchmarks
 
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
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: 160305
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 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: 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: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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: 159729
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 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: 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: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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: 159984
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 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: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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: 159660
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 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: Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site (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: 160742
 
Pollutant: Carbaryl
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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: 0 of 1 samples exceeded the water quality threshold for Carbaryl.
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: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
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
 
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: 9
Number of Exceedances: 1
 
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: 3
Number of Exceedances: 0
 
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 Carbaryl.
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: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
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
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: 94165
 
Pollutant: Carbofuran
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 0
 
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: 160676
 
Pollutant: Carbofuran
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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: 0 of 1 samples exceeded the water quality threshold for Carbofuran.
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: OPP Aquatic Life Benchmarks
 
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
 
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: 3
Number of Exceedances: 0
 
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 Carbofuran.
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: OPP Aquatic Life Benchmarks
 
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
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: 1
Number of Exceedances: 0
 
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 evaluation guideline for Chlordane .
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: 1
Number of Exceedances: 0
 
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 evaluation guideline for Chlordane .
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: 2
Number of Exceedances: 1
 
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: OPP Aquatic Life Benchmarks
 
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
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: 1
Number of Exceedances: 0
 
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: 0 of 1 samples exceeded the water quality threshold for Cyanazine.
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: OPP Pesticide Ecotoxicity Database.
 
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
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: 94063
 
Pollutant: Cyfluthrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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 for this line of evidence for Watsonville Slough was collected at 3 monitoring sites [ Pajaro River Estuary-Sediment site 3 - 305PJESD3, Pajaro River Estuary-Sediment site 4 - 305PJESD4, 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): 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: 3
Number of Exceedances: 0
 
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: 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 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: 152163
 
Pollutant: Cyfluthrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Cyfluthrin, total .
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: 3
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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 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
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: 152449
 
Pollutant: Cyhalothrin, Lambda
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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 Cyhalothrin, Total lambda- .
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 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 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: 152663
 
Pollutant: Cyhalothrin, Lambda
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
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 Cyhalothrin, Total lambda- .
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: 58861
 
Pollutant: Cyhalothrin, Lambda
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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 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 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: 9
Number of Exceedances: 0
 
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: 9
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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 for this line of evidence for Watsonville Slough was collected at 3 monitoring sites [ Pajaro River Estuary-Sediment site 3 - 305PJESD3, Pajaro River Estuary-Sediment site 4 - 305PJESD4, 305WAT-Watsonville Slough below Beach Street Input - 305WAB]
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
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: 94169
 
Pollutant: Cypermethrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Estuarine Habitat
 
Number of Samples: 9
Number of Exceedances: 0
 
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: 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 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: 9
Number of Exceedances: 0
 
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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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 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: Data for this line of evidence for Watsonville Slough was collected at 3 monitoring sites [ Pajaro River Estuary-Sediment site 3 - 305PJESD3, Pajaro River Estuary-Sediment site 4 - 305PJESD4, 305WAT-Watsonville Slough below Beach Street Input - 305WAB]
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: 152875
 
Pollutant: Cypermethrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 3
Number of Exceedances: 0
 
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 Cypermethrin, 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: 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: 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 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: 9
Number of Exceedances: 0
 
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: 1
Number of Exceedances: 0
 
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 Cypermethrin, Total .
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 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: 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
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: 94049
 
Pollutant: DDD (Dichlorodiphenyldichloroethane)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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: 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 3 monitoring sites [ Pajaro River Estuary-Sediment site 3 - 305PJESD3, Pajaro River Estuary-Sediment site 4 - 305PJESD4, 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): 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: 2
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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: 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: 1
Number of Exceedances: 1
 
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 1 samples exceeded the evaluation guideline for DDD (Dichlorodiphenyldichloroethane) .
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
 
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: 3
Number of Exceedances: 0
 
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: 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. There shall be no increase in pesticide concentrations found in bottom sediments or aquatic life (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: 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.
 
 
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: 94083
 
Pollutant: DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 0
 
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 Mar