Final California 2018 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name: Stillwater Cove Regional Park Beach
Water Body ID: CAC1138503220081029143200
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
73227
Region 1     
Stillwater Cove Regional Park Beach
 
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)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: Fecal indicator bacteria (which includes enterococcus, fecal coliform, and total colifrom) are 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 (LOE) is necessary to assess listing status. Five LOEs are available in the administrative record to assess indicator bacteria in this water body for the protection of contact recreation (REC-1). Additionally, one LOE is available to assess shellfish harvesting beneficial use (SHELL)

Data from LOE 32691 were re-evaluated with LOEs 133658 and 133688. Data from LOE 44733 were re-evaluated with LOEs 133699 and 133610. Data from LOE 25308 were re-evaluated with LOE 133658, 133688, 133699, and 133610. Data from LOEs 47607 and 47606 were re-evaluated with LOE 133607.

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". However, the data assessed in this decision include data collected during months outside the April - October range. Therefore, this pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy, using a 10% exceedance rate. LOEs 133688 and 133699 were not used, because they were assessed at a 4% exceedance rate.

The following summary presents the total number of exceedances and total sample count: 1) 15 of 120 samples exceed the statistical threshold value (STV) objective for enterococcus for REC-1; 2) 15 of 382 samples exceed the geometric mean objective for enterococcus for REC-1; 3) 0 of 189 samples exceed the singles sample maximum objective for fecal coliform for REC-1; 4) 0 of 119 samples exceed the geometric mean objective for fecal coliform for REC-1; and 5) 31 of 474 samples exceed the median concentration objective for total coliform for SHELL.

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 (i.e., sufficient justification to not list). This conclusion is based on the staff findings that: (1) The data used satisfy the data quality requirements of Section 6.1.4 of the Policy. (2) The data used satisfy 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 listed in Table 3.2 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:
 
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 47607
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 103
Number of Exceedances: 7
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: 7 of 103 samples exceed the objective of 70 MPN/100mL applied as a rolling 30 day geomean for Total Coliform.
Data Reference: Data for Region 1 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, the median total coliform density shall not exceed 70 per 100 mL. Staff applied the objective as a rolling 30 day geometric mean consistent with other state bacteria objectives and with guidance from the National Shellfish Sanitation Program from which the objectives were taken.
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 Stillwater Cove Regional Park Beach was collected at 1 monitoring site [Still Water Cove Regional Park]
Temporal Representation: Data was collected over the time period 4/2/2007-2/16/2010.
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):
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 133607
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 474
Number of Exceedances: 31
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Sonoma County data for Stillwater Cove Regional Park Beach to determine beneficial use support and the results are as follows: 31 of the 474 samples exceeded the water quality standard for Coliform, Total. 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: The samples were collected at 1 monitoring site(s), station(s): Stillwater
Temporal Representation: The samples were collected between the days of 1999-08-09 and 2017-05-01 .
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.
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 32691
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 103
Number of Exceedances: 7
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Seven of the 103 geomeans exceeded the objective.
Data Reference: Data for Region 1 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for entercoccus states that the entercoccus density shall not exceed 35 per 100 mL. Water Quality Control Plan for Ocean Waters 2009.
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 Still Water Cove Regional Park site.
Temporal Representation: Samples were collected approximately once a week from 2007 to 2010.
Environmental Conditions:
QAPP Information: The samples were collected for the Beach Watch program.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 44733
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 115
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: 6 of 115 samples exceed the criterion for Enterococci.
Data Reference: Data for Region 1 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2009) states that the single sample maximum for Enterococcus shall not exceed 104 MPN/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 Stillwater Cove Regional Park Beach was collected at 1 monitoring site [ Still Water Cove Regional Park]
Temporal Representation: Data was collected over the time period 4/2/2007-2/16/2010.
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):
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 133699
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 107
Number of Exceedances: 11
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Sonoma County data for Stillwater Cove Regional Park Beach to determine beneficial use support and the results are as follows: 11 of the 107 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. 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 for all ocean waters, 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: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): Stillwater
Temporal Representation: The samples were collected between the days of 1999-08-09 and 2017-05-01 .
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.
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 133688
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 349
Number of Exceedances: 7
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Sonoma County data for Stillwater Cove Regional Park Beach to determine beneficial use support and the results are as follows: 7 of the 349 samples exceeded the geomean water quality standard 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 for all ocean waters , is a six-week rolling GM of Enterococci not to exceed 30 cfu/100mL (calculated weekly).
Objective/Criterion Reference: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): Stillwater
Temporal Representation: The samples were collected between the days of 1999-08-09 and 2017-05-01 .
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.
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 47606
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 115
Number of Exceedances: 10
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: 10 of 115 samples exceed the objective of 230 MPN/100mL applied as a single sample maximum for Total Coliform.
Data Reference: Data for Region 1 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The California Ocean Plan states the following: At all areas where shellfish may be harvested for human consumption, the following bacterial objectives shall be maintained throughout the water column: Ten percent of the samples collected during any 30-day period shall not exceed 230 MPN/100mL.
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 Stillwater Cove Regional Park Beach was collected at 1 monitoring site [ Still Water Cove Regional Park]
Temporal Representation: Data was collected over the time period 4/2/2007-2/16/2010.
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):
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 133610
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 120
Number of Exceedances: 15
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Sonoma County data for Stillwater Cove Regional Park Beach to determine beneficial use support and the results are as follows: 15 of the 120 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: 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 for all ocean waters, 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: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): Stillwater
Temporal Representation: The samples were collected between the days of 1999-08-09 and 2017-05-01 .
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.
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 25308
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 74
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: None of the 74 single samples of enterococcus collected at Stillwater Cove Regional Park Beach exceed the objective. Additionally, none of the 16 30-day geomean values exceed the objective. The single sample and geomean values are two different matrices used Sonoma County Division of Environmental Health 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
 
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 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
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Stillwater Cove Regional Park Beach .
Temporal Representation: Samples were collected weekly from April to December 2005 and from April to October 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 in accordance with the procedures described in "Environmental Health Policy and Procedure No. 00-1" (Krug 2000).
QAPP Information Reference(s): Environmental Health Policy and Procedure No. 00-1. Subject: Ocean Water Sampling Program Procedures. County of Sonoma Department of Health Services
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 44596
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 115
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: 0 of 115 samples exceed the criterion for Fecal Coliform.
Data Reference: Data for Region 1 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2009) states that the single sample maximum for fecal coliform shall not exceed 400 MPN/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 Stillwater Cove Regional Park Beach was collected at 1 monitoring site [ Still Water Cove Regional Park]
Temporal Representation: Data was collected over the time period 4/2/2007-2/16/2010.
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):
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 32693
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 103
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 103 geomeans exceeded the objective.
Data Reference: Data for Region 1 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for fecal coliform states that the coliform density shall not exceed 200 MPN per 100 mL. Water Quality Control Plan for Ocean Waters (SWRCB 2009).
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 Still Water Cove Regional Park site.
Temporal Representation: Samples were collected approximately once a week from 2007 to 2010.
Environmental Conditions:
QAPP Information: The samples were collected for the beach watch program.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 25306
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 74
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: None of the 74 single samples of fecal coliform collected at Stillwater Cove Regional Park Beach exceed the objective. Additionally, none of the 16 30-day geomean values exceed the objective. The single sample and geomean values are two different matrices used Sonoma County Division of Environmental Health 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
 
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 Stillwater Cove Regional Park Beach .
Temporal Representation: Samples were collected weekly from April to December 2005 and from April to October 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 in accordance with the procedures described in "Environmental Health Policy and Procedure No. 00-1" (Krug 2000).
QAPP Information Reference(s): Environmental Health Policy and Procedure No. 00-1. Subject: Ocean Water Sampling Program Procedures. County of Sonoma Department of Health Services
 
Line of Evidence (LOE) for Decision ID 73227, Indicator Bacteria
Region 1     
Stillwater Cove Regional Park Beach
 
LOE ID: 133658
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 382
Number of Exceedances: 15
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Sonoma County data for Stillwater Cove Regional Park Beach to determine beneficial use support and the results are as follows: 15 of the 382 samples exceeded the geomean water quality standard for Enterococcus. This is a six week rolling geomean that is calculated weekly.
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 for all ocean waters , is a six-week rolling GM of Enterococci not to exceed 30 cfu/100mL (calculated weekly).
Objective/Criterion Reference: California Ocean Plan Water Quality Control Plan Ocean Waters of California 2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): Stillwater
Temporal Representation: The samples were collected between the days of 1999-08-09 and 2017-05-01 .
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.