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

Supporting Information

Regional Board 1 - North Coast Region

Water Body Name:	Eureka Plain HU, Gannon Slough
Water Body ID:	CAR1100005219990617095337
Water Body Type:	River & Stream


DECISION ID	78175	Region 1
Eureka Plain HU, Gannon Slough

Pollutant:	Indicator Bacteria
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Sources:	A Source Unknown
Expected TMDL Completion Date:	2026
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Fecal indicator bacteria (which includes E. coli and fecal coliform) are being considered for placement on the Section 303(d) list under Section 3.2 and 3.3 of the Listing Policy. Under these sections a single line of evidence (LOE) is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess fecal indicator bacteria in this water body: one for E. coli and one for fecal coliform. All data assessed for this water body were collected in Campbell Creek, and thus this listing Decision will determine if it is appropriate to List Campbell Creek. In accordance with Section 3.3 of the Listing Policy, a 4% exceedance rate shall be used to add waters to the List "if water quality monitoring was conducted April 1 through October 31 only". The E. coli data collected in Campbell Creek (LOE 47486) were collected during this timeframe only. Six of 6 E. coli samples collected in Campbell Creek exceed the evaluation guideline and this violates the allowed 4% exceedance frequency. The fecal coliform data assessed in LOE 31827 for Campbell Creek includes data collected during months outside the April - October range. Therefore, the data are being considered under section 3.2 of the Listing Policy, using a 10% exceedance rate. Seven of 8 fecal coliform samples exceed the evaluation guideline and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for adding Campbell Creek to the Section 303(d) list (i.e., sufficient justification to 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) Six of 6 E. coli samples collected in Campbell Creek exceed the evaluation guideline and this violates the allowed 4% exceedance frequency. (4) Seven of 8 fecal coliform samples exceed the evaluation guideline and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. (5) 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:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.

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 78175, Indicator Bacteria	Region 1
Eureka Plain HU, Gannon Slough

LOE ID:

31827

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:

Seven of the eight samples exceeded the fecal coliform evaluation guideline. Since less than 5 samples over a 30-day period were collected, the evaluation guideline is used for comparison to the samples.

Data Reference:

Data for bacteria in various North Coast Region water bodies

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteriological quality of waters of the North Coast Region shall not be degraded beyond natural background levels. In no case shall coliform concentrations in waters of the North Coast Region exceed the following: In waters designated for contact recreation (REC-1), the median fecal coliform concentration based on a minimum of not less than 5 samples for any 30-day period shall not exceed 50 MPN* / 100 ml, nor shall more than 10% of total samples during any 30-day period exceed 400 MPN / 100 ml. Water Quality Control Plan, North Coast Region (NCRWQCB 2011).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) for the North Coast Region

Evaluation Guideline:

Beach posting is recommended when single sample fecal coliform levels exceed 400 MPN / 100 ml. Draft Guidance for Fresh Water Beaches" (DHS 2011).

Guideline Reference:

Draft Guidance for Fresh Water Beaches. Last Update: May 8, 2006. Initial Draft: November 1997. California Department of Public Health.

Spatial Representation:

The samples were collected at Cambell Creek at 14th and Union and Cambell Creek at 7th.

Temporal Representation:

The samples were collected between October 2005 to May 2008.

Environmental Conditions:

QAPP Information:

The samples were collected under the Redwood Community Action Agency's Humboldt Bay First Flush Quality Assurance Project Plan.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 78175, Indicator Bacteria	Region 1
Eureka Plain HU, Gannon Slough