Draft California 2026 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name: Moonstone County Park
Water Body ID: CAC1081001220070319154339
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
162996
Region 1     
Moonstone County Park
 
Pollutant: Indicator Bacteria
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)(2018)
Revision Status Revised
Sources: A Source Unknown
TMDL Priority: Low
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Lacking constant inputs, indicator bacteria do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Historic lines of evidence for data collected prior to October 21, 2012, were evaluated pursuant to these considerations and were not used to assess water quality standards attainment because they do not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy.

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.

Five lines of evidence are available in the administrative record to assess this pollutant, nine of which contain data collected on or after October 21, 2012. Geometric means are used to assess the data for the REC-1 beneficial use. Where geometric means are not available, statistical threshold values are used. Geometric means are available for Moonstone County Park and will be used for the assessment.

***DO NOT LIST***
*For Fecal Coliform, 0 of 1 single sample maximum exceeds the objective for the REC-1 beneficial use, and this is insufficient data to the allowable frequency for AB411 beaches in the Listing Policy.

***DO NOT DELIST***
*For Enterococcus, 18 of 60 geometric means exceed the objective for the REC-1 beneficial use, and this exceeds the allowable frequency of AB411 beaches in the the Listing Policy.

*For Total Coliform, 8 of 8 weekly medians exceed the objective for the SHELL beneficial use, and this exceeds the allowable frequency in Table 4.2 of the Listing Policy.

*For Total Coliform, 8 of 8 monthly percents exceed the objective for the SHELL beneficial use, and this exceeds the allowable frequency in Table 4.2 of the Listing Policy.

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 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. For the REC-1 beneficial use enterococcus geomean, 18 of 60 geomeans exceed the objective; for the SHELL beneficial use total coliform median concentration, 8 of 8 medians exceed the objective; and for the SHELL beneficial use total coliform SSM, 8 of 8 SSMs exceed the objective, and this exceeds the allowable frequency listed in Table 4.2 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 met.

This listing applies to the entire waterbody.

This listing applies to the entire waterbody.
 
Regional Board Decision Recommendation: After review of the available data and information, 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:
 
 
Line of Evidence (LOE) for Decision ID 162996, Indicator Bacteria
Region 1     
Moonstone County Park
 
LOE ID: 133660
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Humboldt County data for Moonstone County Park to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality standard for Coliform, Fecal. The water quality standard is based on a Single Sample Maximum (SSM) value that is calculated daily.
Data Reference: Humboldt County Beachwatch data reformatted to match CEDEN fields.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2018) states that the Single Sample Maximum concentration of Fecal Coliform shall not exceed 400 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): Moonstone Beach
Temporal Representation: The samples were collected between the days of 2015-09-15 and 2015-09-15 .
Environmental Conditions:
QAPP Information: Data exempt from QAPP requirement. Draft QAPP for Humboldt County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP.
QAPP Information Reference(s): Draft QAPP for Humboldt County Beachwatch data. Represents data collection procedure prior to development of a formal QAPP.
 
Line of Evidence (LOE) for Decision ID 162996, Indicator Bacteria
Region 1     
Moonstone County Park
 
LOE ID: 353458
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Percent
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 8
Number of Exceedances: 8
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Humboldt County data to determine beneficial use support and the results are as follows: 8 of the 8 samples exceeded the water quality standard for Total Coliform. The water quality standard for shellfish is based on the percent of Total Coliform at each station that exceed 230 per 100 mL, and is calculated on a monthly basis.
Data Reference: Humboldt County Beachwatch data reformatted to match CEDEN fields.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Ocean Plan (SWRCB 2018) states that not more than 10 percent of the samples shall exceed 230 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): Moonstone Beach
Temporal Representation: The samples were assessed for the ten years before the close of data solicitation (2012-10-21 to 2022-10-21).
Environmental Conditions:
QAPP Information: Data exempt from QAPP requirement. Draft QAPP for Humboldt County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP.
QAPP Information Reference(s): Draft QAPP for Humboldt County Beachwatch data. Represents data collection procedure prior to development of a formal QAPP.
 
Line of Evidence (LOE) for Decision ID 162996, Indicator Bacteria
Region 1     
Moonstone County Park
 
LOE ID: 353457
 
Pollutant: Total Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Median
 
Beneficial Use: Shellfish Harvesting
 
Number of Samples: 8
Number of Exceedances: 8
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Beachwatch_Humboldt County data to determine beneficial use support and the results are as follows: 8 of the 8 samples exceeded the water quality standard for Total Coliform. 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: Humboldt 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): Moonstone Beach
Temporal Representation: The samples were assessed for the ten years before the close of data solicitation (2012-10-21 to 2022-10-21).
Environmental Conditions:
QAPP Information: Data exempt from QAPP requirement. Draft QAPP for Humboldt County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP.
QAPP Information Reference(s): Draft QAPP for Humboldt County Beachwatch data. Represents data collection procedure prior to development of a formal QAPP.
 
Line of Evidence (LOE) for Decision ID 162996, Indicator Bacteria
Region 1     
Moonstone County Park
 
LOE ID: 353489
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 30
Number of Exceedances: 10
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch-Humboldt County data for Moonstone County Park to determine beneficial use support and the results are as follows: 10 of the 30 samples exceeded the geomean water quality threshold 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: WQ from the BeachWatch for the 2026 Integrated Report in Region 1
 
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): Moonstone Beach
Temporal Representation: Data was assessed for samples collected within 10 years of the close of data solicitation for the 2026 Integrated Report (October 21, 2012 to October 21, 2022).
Environmental Conditions:
QAPP Information: QAPP for BeachWatch
QAPP Information Reference(s): QAPP Reference for Beach Watch Program
 
Line of Evidence (LOE) for Decision ID 162996, Indicator Bacteria
Region 1     
Moonstone County Park
 
LOE ID: 353488
 
Pollutant: Enterococcus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: GeoMean
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 30
Number of Exceedances: 8
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed BeachWatch-Humboldt County data for Moonstone Beach to determine beneficial use support and the results are as follows: 8 of the 30 samples exceeded the geomean water quality threshold 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: Humboldt 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 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): Moonstone Beach
Temporal Representation: Data was assessed for samples collected within 10 years of the close of data solicitation for the 2026 Integrated Report (October 21, 2012 to October 21, 2022).
Environmental Conditions:
QAPP Information: Data exempt from QAPP requirement. Draft QAPP for Humboldt County Beachwatch data used instead. Represents data collection procedure prior to development of a formal QAPP.
QAPP Information Reference(s): Draft QAPP for Humboldt County Beachwatch data. Represents data collection procedure prior to development of a formal QAPP.