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

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name: Pacific Ocean Shoreline, Aliso HSA, Laguna Beach - Treasure Island
Water Body ID: CAC9011300020210923055359
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
150068
Region 9     
Pacific Ocean Shoreline, Aliso HSA, Laguna Beach - Treasure Island
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.2 and 3.3 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant for REC-1. Zero of 427 samples exceed the GM threshold for Enterococci. Zero of 285 samples exceed the GM threshold for Fecal Coliform. Two lines of evidence are available in the administrative record to assess this pollutant for SHELL. One hundred and six out of 645 samples exceed the SHELL threshold for Total Coliform.

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 for impairment of REC-1 and SHELL.

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 427 samples exceeded the Enterococci water quality threshold, and zero of 285 samples exceeded the Fecal Coliform water quality threshold for the protection of REC-1, and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. One hundred and six out of 645 exceed the SHELL threshold for Total Coliform, and this does exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

The Water Quality Control Plan for Ocean Waters (“Ocean Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use: a fecal coliform water quality objective and an enterococci water quality objective. This waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the fecal coliform and enterococci objectives. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. For enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches from April 1 through October 31 only.
 
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: The Water Quality Control Plan for Ocean Waters (“Ocean Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use: a fecal coliform water quality objective and an enterococci water quality objective. This waterbody is being considered for placement on or removal from the CWA section 303(d) List under section 3.3 or 4.3 of the Listing Policy, as applicable, using the fecal coliform and enterococci objectives. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Additionally, water quality conditions in waterbodies may change as a result of management actions that have been implemented to address bacteria. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or missing a human health problem. Historic lines of evidence for data collected prior to 2010 were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. For enterococci data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches from April 1 through October 31 only.
 
State Board Decision Recommendation:
 
 
Line of Evidence (LOE) for Decision ID 150068, Indicator Bacteria
Region 9     
Pacific Ocean Shoreline, Aliso HSA, Laguna Beach - Treasure Island
 
LOE ID: 302959
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 427
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Pacific Ocean Shoreline, Aliso HSA, at Aliso Beach - north to determine beneficial use support and the results are as follows: 0 of the 427 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.
Data Reference: Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2019) states that the bacteria water quality objective to protect the REC-1 beneficial for all ocean waters for Enterococci is a geometric mean (GM) of 30 cfu/100 mL. The waterbody GM shall not be greater that the GM magnitude in any six-week interval, calculated weekly.
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): S11
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2019-06-10 .
Environmental Conditions:
QAPP Information: QAPP for the Orange County Beachwatch data
QAPP Information Reference(s): QAPP for the Orange County Beachwatch data for the 2020 Integrated Report.
 
Line of Evidence (LOE) for Decision ID 150068, Indicator Bacteria
Region 9     
Pacific Ocean Shoreline, Aliso HSA, Laguna Beach - Treasure Island
 
LOE ID: 302960
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 285
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Pacific Ocean Shoreline, Aliso HSA, at Aliso Beach - north to determine beneficial use support and the results are as follows: 0 of the 285 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a 30-Day rolling geomean.
Data Reference: Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2019) states that the 30 day geometric mean of fecal coliform density not exceed 200 per 100 mL, calculated based on the five most recent samples from each site.
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): S11
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2019-06-10 .
Environmental Conditions:
QAPP Information: QAPP for the Orange County Beachwatch data
QAPP Information Reference(s): QAPP for the Orange County Beachwatch data for the 2020 Integrated Report.
 
Line of Evidence (LOE) for Decision ID 150068, Indicator Bacteria
Region 9     
Pacific Ocean Shoreline, Aliso HSA, Laguna Beach - Treasure Island
 
LOE ID: 302961
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 645
Number of Exceedances: 13
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Pacific Ocean Shoreline, Aliso HSA, at Aliso Beach - north to determine beneficial use support and the results are as follows: 13 of the 645 samples exceeded the water quality threshold for Coliform, Total. The water quality threshold for shellfish is based on the median concentration of Total Coliform at each station, and is calculated as a 30-day rolling median.
Data Reference: Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2019) states that the median total coliform density shall not exceed 70 per 100 mL.
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): S11
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2019-06-10 .
Environmental Conditions:
QAPP Information: QAPP for the Orange County Beachwatch data
QAPP Information Reference(s): QAPP for the Orange County Beachwatch data for the 2020 Integrated Report.
 
Line of Evidence (LOE) for Decision ID 150068, Indicator Bacteria
Region 9     
Pacific Ocean Shoreline, Aliso HSA, Laguna Beach - Treasure Island
 
LOE ID: 302962
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 645
Number of Exceedances: 106
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed data for Pacific Ocean Shoreline, Aliso HSA, at Aliso Beach - north to determine beneficial use support and the results are as follows: 106 of the 645 samples exceeded the water quality threshold for Coliform, Total. The water quality threshold is based on a 10% exceedance rate that is calculated for a 30-Day peroid.
Data Reference: Coastal Counties in Region 9 including: Orange, San Diego, and Los Angeles counties.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2019) states that not more than 10 percent of the total coliform samples shall exceed 230 per 100 mL.
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): S11
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2019-06-10 .
Environmental Conditions:
QAPP Information: QAPP for the Orange County Beachwatch data
QAPP Information Reference(s): QAPP for the Orange County Beachwatch data for the 2020 Integrated Report.