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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Castlerock Beach
Water Body ID: CAX4051300020000407104603
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
150282
Region 4     
Castlerock Beach
 
Pollutant: Indicator Bacteria
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 (being addressed by USEPA approved TMDL)(2018)
Revision Status Revised
Sources: Nonpoint Source | Point Source
TMDL Name: Santa Monica Bay Beach Closures/Coliform/Bacteria Indicators (48)
TMDL Project Code: 392
Date TMDL Approved by USEPA: 06/19/2003
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for removal on the CWA section 303(d) List under sections 2.2, 4.3 and 4.11 of the Listing Policy. Under 4.3 of the Policy, a minimum of one line of evidence is needed to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Because a statistically sufficient number of geomean samples were not available, attainment of the bacteria objective was determined based only on the STV per the situation-specific weight of evidence approach outlined in Sections 4.11 of the Listing Policy.

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. There is sufficient justification to place it 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.

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. 4 of 9 samples exceeded the statistical threshold value for Enterococcus and this is insufficient to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using Table 4.2
4. The Santa Monica Bay Bacteria Dry Weather TMDL was approved by RWQCB on January 24, 2002 and subsequently approved by USEPA. The Santa Monica Bay Bacteria Wet Weather TMDL was approved by RWQCB on December 12, 2004 and approved by USEPA on June 19, 2003.
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 there was a previous listing and there are not enough data to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation:
 
 
Line of Evidence (LOE) for Decision ID 150282, Indicator Bacteria
Region 4     
Castlerock Beach
 
LOE ID: 303167
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 9
Number of Exceedances: 4
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed LA County MS4 data for Castlerock Beach to determine beneficial use support and the results are as follows: 4 of the 9 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ data from the MS4 database assembled for the 2024 Integrated Report in Region 4.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters, applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in a calendar month. (Ocean Plan 2019)
Objective/Criterion Reference: SWRCB. 2005. Water Quality Control Plan, Ocean Waters of California (Ocean Plan). California Environmental Protection Agency, State Water Resources Control Board. February 2, 2019
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): SMB-2-01 (NA).
Temporal Representation: The samples were collected between the days of 2016-04-20 and 2018-05-31 .
Environmental Conditions:
QAPP Information: Municipal Separate Storm Sewer System (MS4)
QAPP Information Reference(s): Municipal Separate Storm Sewer System (MS4)
 
Line of Evidence (LOE) for Decision ID 150282, Indicator Bacteria
Region 4     
Castlerock Beach
 
LOE ID: 3618
 
Pollutant: Indicator Bacteria
LOE Subgroup: Pollutant-Water
Matrix: Not Specified
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion:
Objective/Criterion Reference:
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation:
Temporal Representation:
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
 
DECISION ID
69353
Region 4     
Castlerock Beach
 
Pollutant: DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision: List on 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)(2016)
Revision Status Original
Sources: A Source Unknown
TMDL Name: Santa Monica Bay Historic Pesticides (58)
TMDL Project Code: 397
Date TMDL Approved by USEPA: 03/26/2012
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: 303(d) listing decisions made prior to 2006 were not held in an assessment database.

There is sufficient justification to place this waterbody/pollutant in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by USEPA, and is expected to result in attainment of the standard.

This conclusion is based on the staff findings that:
1. The Santa Monica Bay DDT and PCBs TMDL was approved by USEPA on 03/26/2012.
2. 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 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 69353, DDT (Dichlorodiphenyltrichloroethane)
Region 4     
Castlerock Beach
 
LOE ID: 4081
 
Pollutant: DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Not Recorded
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
 
DECISION ID
69354
Region 4     
Castlerock Beach
 
Pollutant: PCBs (Polychlorinated biphenyls)
Final Listing Decision: List on 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)(2016)
Revision Status Original
Sources: A Source Unknown
TMDL Name: Santa Monica Bay Historic Pesticides (58)
TMDL Project Code: 397
Date TMDL Approved by USEPA: 03/26/2012
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: 303(d) listing decisions made prior to 2006 were not held in an assessment database.

There is sufficient justification to place this waterbody/pollutant in the Being Addressed portion of the CWA 303(d) List because a TMDL has been completed and approved by USEPA, and is expected to result in attainment of the standard.

This conclusion is based on the staff findings that:
1. The Santa Monica Bay DDT and PCBs TMDL was approved by USEPA on 03/26/2012.
2. 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 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 69354, PCBs (Polychlorinated biphenyls)
Region 4     
Castlerock Beach
 
LOE ID: 4082
 
Pollutant: PCBs (Polychlorinated biphenyls)
LOE Subgroup: Pollutant-Tissue
Matrix: Tissue
Fraction: Not Recorded
 
Beneficial Use: Commercial or recreational collection of fish, shellfish, or organisms
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):