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

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name:	Old Home Beach
Water Body ID:	CAC1081001220120426090438
Water Body Type:	Coastal & Bay Shoreline


DECISION ID	168925	Region 1
Old Home Beach

Pollutant:	Indicator Bacteria
Final Listing Decision:	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	Original
Reason for Delisting:	Applicable WQS attained; according to new assessment method
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. Six lines of evidence are with data collected since October 21, 2012, are available in the administrative record to assess this pollutant. 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 Old Home Beach and will be used for the assessment. For the REC-1 beneficial use enterococcus geomean, 2 of 31 geomeans exceed the objective. For the SHELL beneficial use total coliform median concentration, 1 of 1 medians exceed the objective. For the SHELL beneficial use total coliform SSM, 1 of 1 SSMs exceed the objective. 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. For the REC-1 beneficial use enterococcus geomean, 2 of 31 geomeans exceed the objective; for the SHELL beneficial use total coliform median concentration, 1 of 1 medians exceed the objective; and for the SHELL beneficial use total coliform SSM, 1 of 1 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.

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

44620

Pollutant:

Fecal Coliform

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:

0 of 21 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 Old Home Beach was collected at 1 monitoring site [ Old Home Beach]

Temporal Representation:

Data was collected over the time period 4/6/2010-8/24/2010.

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

32780

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 18 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 Old Home Beach.

Temporal Representation:

Samples were collected approximately once a week from April 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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

133701

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_Humboldt County data for Old Home Beach to determine beneficial use support and the results are as follows: 2 of the 31 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:

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 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): Old Home Beach

Temporal Representation:

The samples were collected between the days of 2008-10-08 and 2010-10-26 .

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

133655

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:

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 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): Old Home Beach

Temporal Representation:

The samples were collected between the days of 2008-10-08 and 2010-10-26 .

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

44429

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:

0 of 21 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 Old Home Beach was collected at 1 monitoring site [ Old Home Beach]

Temporal Representation:

Data was collected over the time period 4/6/2010-8/24/2010.

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

32778

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:

Not Specified

Data Used to Assess Water Quality:

Zero of the 18 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 Old Home Beach.

Temporal Representation:

Samples were collected approximately once a week from April 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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

133686

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_Humboldt County data for Old Home Beach to determine beneficial use support and the results are as follows: 3 of the 15 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:

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 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): Old Home Beach

Temporal Representation:

The samples were collected between the days of 2008-10-08 and 2010-10-26 .

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

133604

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:

Data Reference:

Humboldt County Beachwatch data reformatted to match CEDEN fields.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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): Old Home Beach

Temporal Representation:

The samples were collected between the days of 2008-10-08 and 2010-10-26 .

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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

353460

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Percent

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

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: 1 of the 1 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): Old Home 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 168925, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

353459

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Median

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

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: 1 of the 1 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): Old Home 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.