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

Supporting Information

Regional Board 2 - San Francisco Bay Region

Water Body Name: Gull Park (San Mateo County)
Water Body ID: CAC2044004020210623045421
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
148783
Region 2     
Gull Park (San Mateo County)
 
Pollutant: Indicator Bacteria
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Sources: A Source Unknown
Expected TMDL Completion Date: 2037
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under sections 2.2 and 3.3 of the Listing Policy. Under section 3.3 of the Policy, a minimum of one line of evidence is needed to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Twenty out of fifty-eight samples exceeded the geometric mean bacteria objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on 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. Twenty of fifty-eight samples exceed the bacteria objectives and this exceeds 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 be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
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 148783, Indicator Bacteria
Region 2     
Gull Park (San Mateo County)
 
LOE ID: 300015
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 58
Number of Exceedances: 20
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_San Mateo County data for Gull Park (San Mateo County) to determine beneficial use support and the results are as follows: 20 of the 58 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 use where the salinity is 1 ppth or higher 95 percent or more of the time applies a six-week rolling geomean to enterococcus, not to exceed 30 cfu/100mL. (ISWEBE 2018)
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: The samples were collected at 1 monitoring site(s), station(s): Gull Park, Foster City (Gull Park, Foster City).
Temporal Representation: The samples were collected between the days of 2019-02-04 and 2020-10-13 .
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 148783, Indicator Bacteria
Region 2     
Gull Park (San Mateo County)
 
LOE ID: 299993
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: STV
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 19
Number of Exceedances: 4
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch_San Mateo County data for Gull Park (San Mateo County) to determine beneficial use support and the results are as follows: 4 of the 19 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 where the salinity is 1 ppth or higher 95 percent or more of the time 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. (ISWEBE 2018)
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: The samples were collected at 1 monitoring site(s), station(s): Gull Park, Foster City (Gull Park, Foster City).
Temporal Representation: The samples were collected between the days of 2019-02-04 and 2020-10-13 .
Environmental Conditions:
QAPP Information: State Board Staff. 2021. QAPP Reference for Beach Watch Program.
QAPP Information Reference(s): QAPP Reference for Beach Watch Program