| Water Body Name: | Gualala Regional Park Beach |
| Water Body ID: | CAC1138503020081029150443 |
| Water Body Type: | Coastal & Bay Shoreline |
DECISION ID |
161537 |
Region 1 |
Gualala Regional Park Beach |
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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: | 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. Lacking constant inputs, indicator bacteria do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of 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. Historic lines of evidence for data collected prior to October 21, 2012, 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. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Geometric means are used to assess the data for the REC-1 beneficial use. Where geometric means are not available, statistical threshold values are used. Geometric means are available for Gualala Regional Park Beach and will be used for the assessment. ***DO NOT LIST*** *For Enterococcus, 0 of 68 geometric means exceed the objective for the REC-1 beneficial use, and this does not exceed the allowable frequency of AB411 beaches in the the Listing Policy. *For Total Coliform, 0 of 7 weekly medians exceed the objective for the SHELL beneficial use, and this is insufficient information to apply Table 4.2 of the Listing Policy. *For Total Coliform, 0 of 7 monthly percents exceed the objective for the SHELL beneficial use, and this is insufficient information to apply Table 4.2 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. For Enterococcus, 0 of 68 geometric means exceed the objective for the REC-1 beneficial use, and this does not exceed the allowable frequency of AB411 beaches in the the Listing Policy. For Total Coliform, 0 of 7 weekly medians exceed the objective for the SHELL beneficial use, and this is insufficient information to apply Table 4.2 of the Listing Policy. For Total Coliform, 0 of 7 monthly percents exceed the objective for the SHELL beneficial use, and this is insufficient information to apply Table 4.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | |
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| LOE ID: | 353545 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | GeoMean | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 39 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BeachWatch_Sonoma County data to determine beneficial use support and the results are as follows: 0 of the 39 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly. This data is for an AB411 beach. This LOE specifically corresponds with dry weather samples and only includes samples collected between April 1 and October 31 of each year. | ||||
| Data Reference: | WQ from the BeachWatch for the 2026 Integrated Report in Region 1 | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial in ocean waters applies a six-week rolling geomean to enterococcus, not to exceed 30 cfu/100mL. (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): Gualala | ||||
| Temporal Representation: | Data was assessed for samples collected within 10 years of the close of data solicitation for the 2026 Integrated Report (October 21, 2012 to October 21, 2022). | ||||
| Environmental Conditions: | |||||
| QAPP Information: | QAPP for BeachWatch | ||||
| QAPP Information Reference(s): | QAPP Reference for Beach Watch Program | ||||
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| LOE ID: | 353544 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | GeoMean | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 29 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed BeachWatch_Sonoma County data to determine beneficial use support and the results are as follows: 0 of the 29 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly. This data is for an AB411 beach. This LOE specifically corresponds with dry weather samples and only includes samples collected between April 1 and October 31 of each year. | ||||
| Data Reference: | Sonoma County Beachwatch data reformatted to match CEDEN fields. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial in ocean waters applies a six-week rolling geomean to enterococcus, not to exceed 30 cfu/100mL. (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): Gualala | ||||
| Temporal Representation: | Data was assessed for samples collected within 10 years of the close of data solicitation for the 2026 Integrated Report (October 21, 2012 to October 21, 2022). | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Data exempt from QAPP requirement. Draft QAPP for Sonoma County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP. | ||||
| QAPP Information Reference(s): | Draft QAPP for Sonoma County Beachwatch. Represents data collection procedure prior to development of a formal QAPP. | ||||
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| LOE ID: | 353447 | ||||
| Pollutant: | Total Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Percent | ||||
| Beneficial Use: | Shellfish Harvesting | ||||
| Number of Samples: | 7 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Beachwatch_Sonoma County data to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the water quality standard for Total Coliform. The water quality standard for shellfish is based on the percent of Total Coliform at each station, and is calculated on a monthly basis. | ||||
| Data Reference: | Sonoma County Beachwatch data reformatted to match CEDEN fields. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | California Ocean Plan (SWRCB 2018) states that 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: | Samples were collected at Gualala. | ||||
| Temporal Representation: | The samples were assessed for data within 10 years of the close of data solicitation (October 21, 2012 to October 22, 2022). | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Data exempt from QAPP requirement. Draft QAPP for Sonoma County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP. | ||||
| QAPP Information Reference(s): | Draft QAPP for Sonoma County Beachwatch. Represents data collection procedure prior to development of a formal QAPP. | ||||
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| LOE ID: | 353446 | ||||
| Pollutant: | Total Coliform | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Median | ||||
| Beneficial Use: | Shellfish Harvesting | ||||
| Number of Samples: | 7 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Beachwatch_Sonoma County data to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the water quality standard for Total Coliform. The water quality standard for shellfish is based on the median concentration of Total Coliform at each station, and is calculated on a monthly basis. | ||||
| Data Reference: | Sonoma County Beachwatch data reformatted to match CEDEN fields. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | California Ocean Plan (SWRCB 2018) states that the median concentration of total coliform samples shall not exceed 70 per 100 ml. | ||||
| Objective/Criterion Reference: | California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009 | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | Samples were collected at Gualala. | ||||
| Temporal Representation: | The samples were assessed for data within 10 years of the close of data solicitation (October 21, 2012 to October 22, 2022). | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Data exempt from QAPP requirement. Draft QAPP for Sonoma County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP. | ||||
| QAPP Information Reference(s): | Draft QAPP for Sonoma County Beachwatch. Represents data collection procedure prior to development of a formal QAPP. | ||||