Final California 2010 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name: Clam Beach (near Strawberry Creek)
Water Body ID: CAC1091002020070319150720
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
6236
Region 1     
Clam Beach (near Strawberry Creek)
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2019
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Indicator bacteria (which includes enterococcus, fecal coliform, and total coliform) for Clam Beach County Park is being considered for removal from the Section 303(d) list under Section 4.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Four 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 Humboldt County in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. In accordance with Section 4.3 of the Listing Policy, a 4% exceedance percentage shall be used to remove waters from the List. This equates to no more than 8 exceedances for enterococcus single samples and no more than 3 for enterococcus 30-day geomean values. For enterococcus, 14 out of 204 single samples exceed the objective and 8 out of 63 30-day geomean values exceed the objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list (i.e., sufficient justification to not de-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 exceed the objectives more than the allowable frequency identified in Section 4.3 of the Listing Policy. (4) Pursuant to Section 4.11 of the Listing Policy, no additional data and information are available indicating that enterococcus standards are met.
 
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 removed from the Section 303(d) List because applicable water quality standards for the pollutant are being exceeded.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
USEPA Action (if applicable): USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.
 
 
Line of Evidence (LOE) for Decision ID 6236, Indicator Bacteria
Region 1     
Clam Beach (near Strawberry Creek)
 
LOE ID: 8836
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 63
Number of Exceedances: 8
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Eight of the 63 30-day geomean values of fecal coliform collected at Clam Beach County Park exceed the objective. Additionally, 14 of the 204 single samples exceed the objective. The single sample and geomean values are two different matrices used to analyzed the same data. Samples were collected by Humboldt County 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 (NCRWQCB 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
 
SWAMP Data: Non-SWAMP
 
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: 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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Clam Beach County Park.
Temporal Representation: Samples were collected weekly from January to December 2004 to 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: Quality control procedures were conducted in accordance with Humboldt County Division of Environmental Health's "Beach Act Monitoring and Notification Program" (Humboldt County 2007).
QAPP Information Reference(s): Beach Act Monitoring and Notification Program. Application Workplan
 
Line of Evidence (LOE) for Decision ID 6236, Indicator Bacteria
Region 1     
Clam Beach (near Strawberry Creek)
 
LOE ID: 8835
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 77
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Two of the 77 single samples of fecal coliform collected at Clam Beach County Park exceed the objective. Additionally, none of the 24 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 Humboldt County 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 (NCRWQCB 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
 
SWAMP Data: Non-SWAMP
 
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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Clam Beach County Park.
Temporal Representation: Samples were collected weekly from January to December 2004 to 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: Quality control procedures were conducted in accordance with Humboldt County Division of Environmental Health's "Beach Act Monitoring and Notification Program" (Humboldt County 2007).
QAPP Information Reference(s): Beach Act Monitoring and Notification Program. Application Workplan
 
Line of Evidence (LOE) for Decision ID 6236, Indicator Bacteria
Region 1     
Clam Beach (near Strawberry Creek)
 
LOE ID: 342
 
Pollutant: Indicator Bacteria
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 78
Number of Exceedances: 5
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Available data indicate sufficient exceedances of bacterial indicator samples. There were 5 out of 78 samples that exceeded the geomean for enterococci (USEPA, 2007).
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Title 17 C.C.R. Section 7958 states that based on a single sample, the density of bacteria in water from each sampling station at a public beach or public water contact sports area shall not exceed:
(A) 1,000 total coliform bacteria per 100 milliliters, if the ratio of fecal/total coliform bacteria exceeds 0.1; or
(B) 10,000 total coliform bacteria per 100 milliliters; or
(C) 400 fecal coliform bacteria per 100 milliliters; or
(D) 104 enterococcus bacteria per 100 milliliters.

Based on the mean of the logarithms of the results of at least five weekly samples during any 30-day sampling period, the density of bacteria in water from any sampling station at a public beach or public water contact sports area, shall not exceed:
(A) 1,000 total coliform bacteria per 100 milliliters; or
(B) 200 fecal coliform bacteria per 100 milliliters; or
(C) 35 enterococcus bacteria per 100 milliliters. (DHS, 1999)
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Station ID# HC40
Temporal Representation: 02/11/2003-10/11/2005
Environmental Conditions:
QAPP Information: Data record: 2003-2005, Humboldt County Health Dept.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 6236, Indicator Bacteria
Region 1     
Clam Beach (near Strawberry Creek)
 
LOE ID: 8834
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 63
Number of Exceedances: 3
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Three of the 63 30-day geomean values of total coliform collected at Clam Beach County Park exceed the objective. Additionally, none of the 202 single samples exceed the objective. The single sample and geomean values are two different matrices used to analyzed the same data. Samples were collected by the Humboldt County 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 (NCRWQCB 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
 
SWAMP Data: Non-SWAMP
 
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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Clam Beach County Park.
Temporal Representation: Samples were collected weekly from January to December 2004 to 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: Quality control procedures were conducted in accordance with Humboldt County Division of Environmental Health's "Beach Act Monitoring and Notification Program" (Humboldt County 2007).
QAPP Information Reference(s): Beach Act Monitoring and Notification Program. Application Workplan