Final California 2024 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	78126	Region 1
Old Home Beach

Pollutant:	Indicator Bacteria
Final Listing Decision:	Do Not 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
Sources:	A Source Unknown
Expected TMDL Completion Date:	2022
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Fecal indicator bacteria (which includes enterococcus, fecal coliform, and total coliform) are being considered for removal from the Section 303(d) list under Section 4.3 of the Listing Policy. Four LOEs are available in the administrative record to assess indicator bacteria in this water body for the attainment of water contact recreation standards (REC-1): two for enterococcus and two for fecal coliform. Additionally, one LOE is available for total coliform for the attainment of shellfish harvesting standards (SHELL). Data from LOEs 47601 and 47600 were re-evaluated with LOE 133648. Data from LOE 44429 were re-evaluated with LOE 133686 and 133604. Data from LOE 32778 were re-evaluated with LOEs 133655 and 133701. The data assessed were ocean beach bacteria data collected in accordance with AB411 (Chapter 765, Statutes of 1997) requirements. This waterbody and pollutant were listed utilizing a 4% exceedance rate under section 3.3 of the Listing Policy, therefore a 4% exceedance rate was used for de-listing. LOEs 133604 and 133655 were not used in this assessment as they were evaluated at the 10% exceedance rate. The following summary presents the total number of exceedances and total sample count: 1) 2 of 31 samples exceed the geometric mean objective for enterococcus for REC-1; 2) 3 of 15 samples exceed the Statistical Threshold Value (STV) objective for enterococcus for REC-1; 3) 0 of 21 samples exceed the single sample maximum objective for fecal coliform for REC-1; 4) 0 of 18 samples exceed the geometric mean objective for fecal coliform for REC-1; and 5) 24 of 36 samples exceed the median concentration objective for total coliform for SHELL Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for removing this water segment-pollutant combination to the Section 303(d) list. This conclusion is based on the staff findings that: (1) The data used satisfy the data quality requirements of Section 6.1.4 of the Policy. (2) The data used satisfy the data quantity requirements of Section 6.1.5 of the Policy. (3) Enterococcus samples for geometric do not exceed the objectives more than the allowable frequency identified in Section 4.3 of the Listing Policy. (4) Fecal coliform samples are insufficient to conclude whether objectives for fecal coliform were met. (5) Total coliform samples related to the SHELL beneficial use exceed the median concentration objective more that the allowable frequency identified in section 4.3 of the Listing Policy (5) Pursuant to Section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are being 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 78126, 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:

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 78126, 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 78126, 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 78126, 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:

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 78126, 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 78126, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

47601

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

4 of 21 samples exceed the objective of 230 MPN/100mL applied as a single sample maximum for Total Coliform.

Data Reference:

Data for Region 1 Beach Watch.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Ocean Plan states the following: At all areas where shellfish may be harvested for human consumption, the following bacterial objectives shall be maintained throughout the water column: Ten percent of the samples collected during any 30-day period shall not exceed 230 MPN/100mL.

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 78126, 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 78126, 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 78126, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

133648

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

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 for Old Home Beach to determine beneficial use support and the results are as follows: 24 of the 36 samples exceeded the water quality standard for Coliform, Total. 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 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 78126, Indicator Bacteria	Region 1
Old Home Beach

LOE ID:

47600

Pollutant:

Total Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Shellfish Harvesting

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

18 of 18 samples exceed the objective of 70 MPN/100mL applied as a rolling 30 day geomean for Total Coliform.

Data Reference:

Data for Region 1 Beach Watch.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Ocean Plan states that at all areas where shellfish may be harvested for human consumption, the median total coliform density shall not exceed 70 per 100 mL. Staff applied the objective as a rolling 30 day geometric mean consistent with other state bacteria objectives and with guidance from the National Shellfish Sanitation Program from which the objectives were taken.

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 78126, 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.