Draft California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name:	Fort Baker, Horseshoe Cove (San Francisco Bay, Central)
Water Body ID:	CAC2031201020110712225614
Water Body Type:	Coastal & Bay Shoreline


DECISION ID	97507	Region 2
Fort Baker, Horseshoe Cove (San Francisco Bay, Central)

Pollutant:	Indicator Bacteria
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Reason for Delisting:	Applicable WQS attained; due to change in WQS
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. All available enterococcus data (2005 through May 2017) were evaluated for this assessment. Fifty-eight of six hundred fifteen samples exceeded the geometric mean objective. Consistent with the contact recreation water quality objective provided in the Inland Surface Waters Enclosed Bays and Estuaries Plan, only the geomean was used to determine use attainment because there were enough samples to calculate the geomean. This waterbody was originally listed based on exceedance of a total coliform objective from SF Bay Basin Plan. This total coliform objective no longer exists so we reassessed all available enterococcus data. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the CWA 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. Fifty-eight of six hundred fifteen samples exceeded the geometric mean objective and this does not exceed the allowable frequency listed in Table 4.2 (exceedance frequency adjusted appropriately for April-October sampling) of the Listing Policy. 4. Pursuant to section 4.11 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 be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 97507, Indicator Bacteria	Region 2
Fort Baker, Horseshoe Cove (San Francisco Bay, Central)

LOE ID:

96988

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

306

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed BeachWatch data for Fort Baker Horseshoe Cove, Northeast site, to determine beneficial use support and results are as follows: thirty of the three hundred six geometric means (calculated weekly) exceeded the objective. We required a minimum of 5 samples to compute each valid geomean, consistent with the objective.

Data Reference:

Beach Watch Data for Six SF Bay Regional Water Quality Control Board Beaches for 2018 Listing Cycle

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The objective is a geometric mean, calculated weekly as a six-week rolling geometric mean, not to exceed 30 cfu/100 mL.

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:

Samples were collected at the Fort Baker Horseshoe Cove, Northeast site.

Temporal Representation:

The data were collected April through October, for the years 2005 through May 2017. This LOE replaces #90605, which included data collected from April 2005 to August 2010. This new LOE also includes data collected from 2010 through 2017 and is based on an analysis of these data in comparison to the newly adopted enterococcus objectives to protect contact recreation.

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 97507, Indicator Bacteria	Region 2
Fort Baker, Horseshoe Cove (San Francisco Bay, Central)

LOE ID:

96990

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed BeachWatch data for Fort Baker Horseshoe Cove, Northwest and Southwest sites, to determine beneficial use support and results are as follows: sixteen of ninety-five STVs (calculated monthly) exceeded the objective.

Data Reference:

Beach Watch Data for Six SF Bay Regional Water Quality Control Board Beaches for 2018 Listing Cycle

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The objective 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:

Samples were collected at the Fort Baker Horseshoe Cove, Northwest site and Southwest site. These stations are within 200 meters and the results were averaged.

Temporal Representation:

The data were collected April through October, for the years 2005 through May 2017. This LOE replaces #90753, which included data collected from April 2005 to August 2010. This new LOE also includes data from 2010 through May 2017 and is based on an analysis of all available data in comparison to the newly adopted enterococcus objectives to protect contact recreation.

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 97507, Indicator Bacteria	Region 2
Fort Baker, Horseshoe Cove (San Francisco Bay, Central)

LOE ID:

96991

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed BeachWatch data for Fort Baker Horseshoe Cove, Northeast site, to determine beneficial use support and results are as follows: thirteen of the ninety-five STVs (calculated monthly) exceeded the objective.

Data Reference:

Beach Watch Data for Six SF Bay Regional Water Quality Control Board Beaches for 2018 Listing Cycle

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The objective 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:

Samples were collected at the Fort Baker Horseshoe Cove, Northeast site.

Temporal Representation:

The data were collected April through October, for the years 2005 through May 2017.This LOE replaces #90754, which included data collected from April 2005 to August 2010. This new LOE also includes data from 2010 through May 2017 and is based on an analysis of all available data in comparison to the newly adopted enterococcus objectives to protect contact recreation.

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 97507, Indicator Bacteria	Region 2
Fort Baker, Horseshoe Cove (San Francisco Bay, Central)

LOE ID:

96989

Pollutant:

Enterococcus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

309

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed BeachWatch data for Fort Baker Horseshoe Cove, Northwest and Southwest sites, to determine beneficial use support and results are as follows: twenty-eight of three hundred nine geometric means (calculated weekly) exceeded the objective. We required a minimum of 5 samples to compute each valid geomean, consistent with the objective.

Data Reference:

Beach Watch Data for Six SF Bay Regional Water Quality Control Board Beaches for 2018 Listing Cycle

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The objective is a six-week rolling geometric mean (calculated weekly), not to exceed 30 cfu/100 mL.

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:

Samples were collected at the Fort Baker Horseshoe Cove, Northwest site and Southwest site. These stations are within 200 meters and the results were averaged.

Temporal Representation:

The data were collected April through October, for the years 2005 through May 2017. This LOE replaces #90606, which included data collected from April 2005 to August 2010. This new LOE also includes data collected from 2010 through May 2017 and is based on an analysis of all available data in comparison to the newly adopted enterococcus objectives to protect contact recreation.

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):