| 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 |
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| Regional Board Conclusion: |
Indicator bacteria (which includes enterococcus, fecal coliform, and total coliform) is being considered for placement on the Section 303(d) list under Section 3.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess indicator bacteria. Data assessed for the 2008 Integrated Report include ocean beach bacteria data collected by the Mendocino County Environmental Health Division in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. In accordance with Section 3.3 of the Listing Policy, a 4% exceedance percentage shall be used to add waters to the List. This equates to no more than 2 exceedances each for enterococcus, fecal coliform, and total coliform single sample values. This also equates to no more than 1 exceedance each for enterococcus, fecal coliform, and total coliform 30-day geomean values. None of the enterococcus, fecal coliform, and total coliform samples (both single samples and geomean values) exceed the objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against adding this water segment-pollutant combination to the Section 303(d) list (i.e., sufficient justification to not 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, fecal coliform, and total coliform samples do not exceed the objectives more than the allowable frequency 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 not met. |
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| Regional Board Decision Recommendation: |
After review of the available data and information, North Coast 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. |
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| State Board Review of Regional Board Conclusion and Recommendation: |
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| 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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| USEPA Action (if applicable): |
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Line of Evidence (LOE) for Decision ID 11852, Indicator Bacteria
|
Region 1 |
Big River Beach at Mendocino Bay |
|
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| LOE ID: |
25258 |
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| Pollutant: |
Enterococcus |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
Total |
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| Beneficial Use: |
Water Contact Recreation |
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| Number of Samples: |
56 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PATHOGEN MONITORING |
| Data Used to Assess Water Quality: |
None of the 56 single samples of enterococcus collected at Big River Beach at Mendocino Bay exceed the objective. Additionally, none of the 14 30-day geomean values exceed the objective. The single sample and geomean values are two different matrices used to analyzed the same data. Samples were collected by the Mendocino County Environmental Health Division in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. Data is maintained by the State Water Board's Beach Watch program. Data is summarized by the North Coast Regional Water Board (North Coast RWQCB 2007). |
| Data Reference: |
North Coast Beach Watch Data. Bacteria data collected by Del Norte County, Humboldt County, Mendocino County Environmental Health Division, Sonoma County Division of Environmental Health, and Marin County in accordance with AB411. Data managed by the State Water Resources Control Board's Beach Watch program at beachwatch.waterboards.ca.gov. Includes data from 2004 to 2006 |
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| SWAMP Data: |
Non-SWAMP |
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| Water Quality Objective/Criterion: |
Per the Ocean Plan (SWRCB 2005): The following bacterial objectives shall be maintained throughout the water column. The following standard is based on the 30-day geometric mean of the 5 most recent samples from each site: Enterococcus density shall not exceed 35 MPN per 100ml. The following standard is for the single sample maximum: Enterococcus density shall not exceed 104 per 100 ml. *Note: MPN is the most probable number of coliform units. |
| Objective/Criterion Reference: |
Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Samples were collected at the Big River Beach at Mendocino Bay, which is part of the Big River-Mendocino Headlands State Park. |
| Temporal Representation: |
Samples were collected weekly from April through October in 2005 and 2006. |
| Environmental Conditions: |
Samples were collected during the dry season. Otherwise, there are no known environmental conditions (e.g., land use practices, fire events, storms, etc.) that are related to these data. |
| QAPP Information: |
Samples were collected and analyzed in accordance with the Sampling and Analysis Plan and the Laboratories and Laboratory Analyses procedures described in the "Draft Guidance for Salt Water Beaches" (DHS 2006). |
| QAPP Information Reference(s): |
Draft Guidance for Salt Water Beaches. Last Update: April 10, 2006. Initial Draft: November 1997. Division of Drinking Water and Environmental Management, California Department of Health Services |
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Line of Evidence (LOE) for Decision ID 11852, Indicator Bacteria
|
Region 1 |
Big River Beach at Mendocino Bay |
|
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| LOE ID: |
25259 |
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| Pollutant: |
Fecal Coliform |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
Total |
| |
| Beneficial Use: |
Water Contact Recreation |
| |
| Number of Samples: |
56 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PATHOGEN MONITORING |
| Data Used to Assess Water Quality: |
None of the 56 single samples of fecal coliform collected at Big River Beach at Mendocino Bay exceed the objective. Additionally, none of the 14 30-day geomean values exceed the objective. The single sample and geomean values are two different matrices used to analyzed the same data. Samples were collected by the Mendocino County Environmental Health Division in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. Data is maintained by the State Water Board's Beach Watch program. Data is summarized by the North Coast Regional Water Board (North Coast RWQCB 2007). |
| Data Reference: |
North Coast Beach Watch Data. Bacteria data collected by Del Norte County, Humboldt County, Mendocino County Environmental Health Division, Sonoma County Division of Environmental Health, and Marin County in accordance with AB411. Data managed by the State Water Resources Control Board's Beach Watch program at beachwatch.waterboards.ca.gov. Includes data from 2004 to 2006 |
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| SWAMP Data: |
Non-SWAMP |
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| Water Quality Objective/Criterion: |
Per the Ocean Plan (SWRCB 2005): The following bacterial objectives shall be maintained throughout the water column. The following standard is based on the 30-day geometric mean of the five most recent samples from each site: Fecal coliform density shall not exceed 200 MPN per 100 ml. The following standard is for the single sample maximum: Fecal coliform density shall not exceed 400 per 100ml. *Note: MPN is the most probable number of coliform units. |
| Objective/Criterion Reference: |
Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Samples were collected at the Big River Beach at Mendocino Bay, which is part of the Big River-Mendocino Headlands State Park. |
| Temporal Representation: |
Samples were collected weekly from April through October in 2005 and 2006. |
| Environmental Conditions: |
Samples were collected during the dry season. Otherwise, there are no known environmental conditions (e.g., land use practices, fire events, storms, etc.) that are related to these data. |
| QAPP Information: |
Samples were collected and analyzed in accordance with the Sampling and Analysis Plan and the Laboratories and Laboratory Analyses procedures described in the "Draft Guidance for Salt Water Beaches" (DHS 2006). |
| QAPP Information Reference(s): |
Draft Guidance for Salt Water Beaches. Last Update: April 10, 2006. Initial Draft: November 1997. Division of Drinking Water and Environmental Management, California Department of Health Services |
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Line of Evidence (LOE) for Decision ID 11852, Indicator Bacteria
|
Region 1 |
Big River Beach at Mendocino Bay |
|
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| LOE ID: |
25260 |
| |
| Pollutant: |
Total Coliform |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
Total |
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| Beneficial Use: |
Water Contact Recreation |
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| Number of Samples: |
56 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PATHOGEN MONITORING |
| Data Used to Assess Water Quality: |
None of the 56 single samples of total coliform collected at Big River Beach at Mendocino Bay exceed the objective. Additionally, none of the 14 30-day geomean values exceed the objective. The single sample and geomean values are two different matrices used to analyzed the same data. Samples were collected by the Mendocino County Environmental Health Division in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. Data is maintained by the State Water Board's Beach Watch program. Data is summarized by the North Coast Regional Water Board (North Coast RWQCB 2007). |
| Data Reference: |
North Coast Beach Watch Data. Bacteria data collected by Del Norte County, Humboldt County, Mendocino County Environmental Health Division, Sonoma County Division of Environmental Health, and Marin County in accordance with AB411. Data managed by the State Water Resources Control Board's Beach Watch program at beachwatch.waterboards.ca.gov. Includes data from 2004 to 2006 |
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| SWAMP Data: |
Non-SWAMP |
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| Water Quality Objective/Criterion: |
Per the Ocean Plan (SWRCB 2005): The following bacterial objectives shall be maintained throughout the water column. The following standard is based on the 30-day geometric mean of the five most recent samples from each site: Total coliform density shall not exceed 1,000 MPN per 100 ml. The following standard is for the single sample maximum: (i) Total coliform density shall not exceed 10,000 per 100 ml; and (ii) Total coliform density shall not exceed 1,000 per 100 ml when the fecal coliform/total coliform ratio exceeds 0.1. *Note: MPN is the most probable number of coliform units. |
| Objective/Criterion Reference: |
Water Quality Control Plan Ocean Waters of California. California Ocean Plan 2005. Sacramento, CA: State Water Resources Control Board, California Environmental Protection Agency |
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| Evaluation Guideline: |
|
| Guideline Reference: |
| |
| Spatial Representation: |
Samples were collected at the Big River Beach at Mendocino Bay, which is part of the Big River-Mendocino Headlands State Park. |
| Temporal Representation: |
Samples were collected weekly from April through October in 2005 and 2006. |
| Environmental Conditions: |
Samples were collected during the dry season. Otherwise, there are no known environmental conditions (e.g., land use practices, fire events, storms, etc.) that are related to these data. |
| QAPP Information: |
Samples were collected and analyzed in accordance with the Sampling and Analysis Plan and the Laboratories and Laboratory Analyses procedures described in the "Draft Guidance for Salt Water Beaches" (DHS 2006). |
| QAPP Information Reference(s): |
Draft Guidance for Salt Water Beaches. Last Update: April 10, 2006. Initial Draft: November 1997. Division of Drinking Water and Environmental Management, California Department of Health Services |
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