| Water Body Name: | Arena Cove Beach |
| Water Body ID: | CAC1137003020181220046787 |
| Water Body Type: | Coastal & Bay Shoreline |
DECISION ID |
105123 |
Region 1 |
Arena Cove 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: | New Decision |
| Revision Status | Original |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Fecal indicator bacteria (which includes enterococcus, fecal coliform, and total coliform) are being considered for listing in the CWA Section 303(d) list under Section 3.3 of the Listing Policy. Under this section a single line of evidence (LOE) is necessary to assess listing status. One LOE is available in the administrative record to assess indicator bacteria in this water body for the attainment of water contact recreation (REC-1) standards.
The data assessed in this decision are ocean beach bacteria data collected in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. In accordance with Section 3.3 of the Listing Policy, a 4% exceedance rate shall be used to add waters to the List "if water quality monitoring was conducted April 1 through October 31 only". Therefore, this pollutant is being considered for addition to the section 303(d) list under section 3.3 of the Listing Policy at a 4% exceedance rate. The following summary presents the total number of exceedances and total sample count: 0 of 1 samples exceed the Statistical Threshold Value (STV) objective for enterococcus. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for adding this water segment-pollutant combination to 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) Enterococcus samples do not meet data requirements as identified in Section 3.3 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 met. Therefore, a decision assessing this water body cannot be made due to insufficient data. |
| 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: | |
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| LOE ID: | 133597 | ||||
| Pollutant: | Enterococcus | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed Beachwatch_Mendocino County data for Arena Cove Beach to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the Statistical Threshold Value (STV) water quality standard for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly. | ||||
| Data Reference: | Mendocino County Beachwatch data reformatted and renamed to match CEDEN fields. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective to protect the REC-1 beneficial for all waters where the salinity is equal to or greater than 10 ppth 95 percent or more of the time, is a Statistical Threshold Value (STV) of 110 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly). | ||||
| 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): Arena Cove | ||||
| Temporal Representation: | The samples were collected between the days of 2003-03-18 and 2003-03-18 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Data exempt from QAPP requirement. Draft QAPP for Mendocino County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP. | ||||
| QAPP Information Reference(s): | Draft QAPP for Mendocino County Beachwatch. Represents data collection procedure prior to development of a formal QAPP. | ||||