| Water Body Name: | Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River |
| Water Body ID: | CAC9021100020120705163350 |
| Water Body Type: | Coastal & Bay Shoreline |
DECISION ID |
127966 |
Region 9 |
Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River |
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| Pollutant: | Indicator Bacteria |
| 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. 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. 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: | 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: | After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. |
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| LOE ID: | 220073 | ||||
| Pollutant: | Total Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Shellfish Harvesting | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 2 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed data for Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River to determine beneficial use support and the results are as follows: 2 of the 3 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): EH-505 | ||||
| Temporal Representation: | The samples were collected between the days of 2012-02-13 and 2012-02-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | QAPP for San Diego County Beachwatch data | ||||
| QAPP Information Reference(s): | QAPP for San Diego County Beachwatch data for the 2020 Integrated Report. | ||||
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| LOE ID: | 220300 | ||||
| Pollutant: | Total Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Shellfish Harvesting | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 2 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed data for Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River to determine beneficial use support and the results are as follows: 2 of the 3 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): EH-505 | ||||
| Temporal Representation: | The samples were collected between the days of 2012-02-13 and 2012-02-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | QAPP for San Diego County Beachwatch data | ||||
| QAPP Information Reference(s): | QAPP for San Diego County Beachwatch data for the 2020 Integrated Report. | ||||
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| LOE ID: | 220404 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 1 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed data for Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River to determine beneficial use support and the results are as follows: 1 of the 1 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: | 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 statistical value threshold (STV) of 110 cfu/100 mL. The STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner. | ||||
| 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): EH-505 | ||||
| Temporal Representation: | The samples were collected between the days of 2012-02-13 and 2012-02-15 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | QAPP for San Diego County Beachwatch data | ||||
| QAPP Information Reference(s): | QAPP for San Diego County Beachwatch data for the 2020 Integrated Report. | ||||
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| LOE ID: | 74780 | ||||
| Pollutant: | Total Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Shellfish Harvesting | ||||
| Number of Samples: | 2 | ||||
| Number of Exceedances: | 2 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Beach Watch data for Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River to determine beneficial use support and results are as follows: 2 of 2 samples exceed the criterion for Coliform, Total. | ||||
| Data Reference: | Data for Region 9 Beach Watch. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The California Ocean Plan states that at all areas where shellfish may be harvested for human consumption, not more than 10 percent of the samples shall exceed 230 per 100 mL. | ||||
| Objective/Criterion Reference: | California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009 | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Data for this line of evidence for Pacific Ocean Shoreline, Lower Ysidora HSA, north of Santa Margarita River was collected at 1 monitoring site [ Santa Margarita River (NR)] | ||||
| Temporal Representation: | Data was collected over the time period 2/24/2010-2/25/2010. | ||||
| Environmental Conditions: | Staff is not aware of any special conditions that might affect interpretation of the data. | ||||
| QAPP Information: | The samples were collected for the Beach Watch program. | ||||
| QAPP Information Reference(s): | |||||