Draft California 2024 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name: Pacific Ocean at Stinson Beach
Water Body ID: CAC2013001220110712220836
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
148599
Region 2     
Pacific Ocean at Stinson 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)(2018)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Twelve lines of evidence are available in the administrative record to assess this pollutant.

Six of the four hundred sixty seven samples exceed geometric mean objective for Enterococcus.
One of the eight hundred ninety-nine samples exceed the geometric mean objective for Fecal Coliform.

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 in the Water Quality Limited Segments category.

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. Six of the four hundred sixty seven samples exceed geometric mean objective for Enterococcus.
One of the eight hundred ninety-nine samples exceed the geometric mean objective for Fecal Coliform.
These do not exceed 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: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300243
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 0 of the 4 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a 30-Day rolling geomean. 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 data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters applies a 30 day geometric mean of fecal coliform based on the five most recent samples at each site, not to exceed 200 per 100 mL. (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): STINSON BEACH - CENTRAL (STINSON BEACH - CENTRAL-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2015-09-08 and 2015-10-27 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300242
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: SSM
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 8
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a Single Sample Maximum (SSM) value that is calculated daily. 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 data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters applies a single sample maximum of fecal coliform, not to exceed 400 per 100 mL. (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): STINSON BEACH - SOUTH (STINSON BEACH - SOUTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2015-09-08 and 2015-10-27 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300261
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: SSM
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 8
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 1 of the 8 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a Single Sample Maximum (SSM) value that is calculated daily. 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 data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters applies a single sample maximum of fecal coliform, not to exceed 400 per 100 mL. (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): STINSON BEACH - NORTH (STINSON BEACH - NORTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2015-09-08 and 2015-10-27 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300282
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 0 of the 4 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a 30-Day rolling geomean. 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 data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters applies a 30 day geometric mean of fecal coliform based on the five most recent samples at each site, not to exceed 200 per 100 mL. (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): STINSON BEACH - SOUTH (STINSON BEACH - SOUTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2015-09-08 and 2015-10-27 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300523
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: SSM
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 8
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 1 of the 8 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a Single Sample Maximum (SSM) value that is calculated daily. 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 data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters applies a single sample maximum of fecal coliform, not to exceed 400 per 100 mL. (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): STINSON BEACH - CENTRAL (STINSON BEACH - CENTRAL-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2015-09-08 and 2015-10-27 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300539
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 0 of the 4 samples exceeded the water quality threshold for Coliform, Fecal. The water quality threshold is based on a 30-Day rolling geomean. 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 data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters applies a 30 day geometric mean of fecal coliform based on the five most recent samples at each site, not to exceed 200 per 100 mL. (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): STINSON BEACH - NORTH (STINSON BEACH - NORTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2015-09-08 and 2015-10-27 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 299575
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 59
Number of Exceedances: 3
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 3 of the 59 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters, applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in a calendar month. (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): STINSON BEACH - SOUTH (STINSON BEACH - SOUTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2010-09-15 and 2020-10-15 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 299854
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 160
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 0 of the 160 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.
Data Reference: WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
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): STINSON BEACH - NORTH (STINSON BEACH - NORTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2010-09-08 and 2020-10-15 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300157
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 149
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 0 of the 149 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.
Data Reference: WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
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): STINSON BEACH - SOUTH (STINSON BEACH - SOUTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2010-09-15 and 2020-10-15 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 300133
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 65
Number of Exceedances: 10
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 10 of the 65 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters, applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in a calendar month. (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): STINSON BEACH - CENTRAL (STINSON BEACH - CENTRAL-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2010-09-15 and 2020-10-15 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 299810
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 158
Number of Exceedances: 6
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 6 of the 158 samples exceeded the geomean water quality threshold for Enterococcus. This is a six week rolling geomean that is calculated weekly.
Data Reference: WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
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): STINSON BEACH - CENTRAL (STINSON BEACH - CENTRAL-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2010-09-15 and 2020-10-15 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90656
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 134
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 134 geomeans exceeded the objective.
Data Reference: Data for Region 2 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for fecal coliform states that the fecal coliform density shall not exceed 200 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 the South Stinson Beach site.
Temporal Representation: Samples were collected from April 2005 to August 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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90651
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 131
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 131 geomeans exceeded the objective.
Data Reference: Data for Region 2 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for fecal coliform states that the fecal coliform density shall not exceed 200 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 the North Stinson Beach site.
Temporal Representation: Samples were collected from April 2005 to August 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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90650
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 135
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 135 geomeans exceeded the objective.
Data Reference: Data for Region 2 Beach Watch.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The geometric mean standard for fecal coliform states that the fecal coliform density shall not exceed 200 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 the Central Stinson Beach site.
Temporal Representation: Samples were collected from April 2005 to August 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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90814
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 499
Number of Exceedances: 1
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch data for Pacific Ocean at Stinson Beach to determine beneficial use support and results are as follows: 1 of 499 samples exceed the criterion for Coliform, Fecal.
Data Reference: Data for Region 2 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 Pacific Ocean at Stinson Beach was collected at 3 monitoring sites [ Stinson Beach - Central, Stinson Beach - North, Stinson Beach South]
Temporal Representation: Data was collected over the time period 4/7/2005-8/25/2010.
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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90653
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 131
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 131 geomeans exceeded the objective.
Data Reference: Data for Region 2 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 the North Stinson Beach site.
Temporal Representation: Samples were collected from April 2005 to August 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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90648
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 135
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 135 geomeans exceeded the objective.
Data Reference: Data for Region 2 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 the Central Stinson Beach site.
Temporal Representation: Samples were collected from April 2005 to August 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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90905
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 499
Number of Exceedances: 9
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch data for Pacific Ocean at Stinson Beach to determine beneficial use support and results are as follows: 9 of 499 samples exceed the criterion for Enterococci.
Data Reference: Data for Region 2 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 Pacific Ocean at Stinson Beach was collected at 3 monitoring sites [ Stinson Beach - Central, Stinson Beach - North, Stinson Beach South]
Temporal Representation: Data was collected over the time period 4/7/2005-8/25/2010.
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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 90654
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 134
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Zero of the 134 geomeans exceeded the objective.
Data Reference: Data for Region 2 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 the South Stinson Beach site.
Temporal Representation: Samples were collected from April 2005 to August 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 148599, Indicator Bacteria
Region 2     
Pacific Ocean at Stinson Beach
 
LOE ID: 299558
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 66
Number of Exceedances: 5
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_Marin County data for Pacific Ocean at Stinson Beach to determine beneficial use support and the results are as follows: 5 of the 66 samples exceeded the Statistical Threshold Value (STV) water quality threshold for Enterococcus. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 2.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective to protect the REC-1 beneficial use in ocean waters, applies a Statistical Threshold Value to enterococcus of 110 cfu/100 mL, not to be exceeded by more than 10 percent of samples collected within in a calendar month. (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): STINSON BEACH - NORTH (STINSON BEACH - NORTH-Stinson Beach, Marin).
Temporal Representation: The samples were collected between the days of 2010-09-08 and 2020-10-15 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program