Publication Summary

This report is the technical portion of a Total Maximum Daily Load (water cleanup plan) study for fecal coliform (FC) bacteria in the Samish Bay watershed.

Due to nonpoint (diffuse) sources, FC levels did not meet freshwater quality criteria at most of the sites sampled by the Department of Ecology from 2006-2007.

Reductions in FC levels are necessary in the Samish River and its tributaries, in Colony Creek, and in all sloughs to the bay to protect (1) the public from pathogens in freshwater and (2) marine water and shellfish harvesting in Samish Bay.

This report forms the basis to set FC load reductions from nonpoint and point (discrete) sources.

The Washington State Department of Ecology (Ecology) is required, under section 303(d) of the federal Clean Water Act and U.S. Environmental Protection Agency regulations, to develop and implement Total Maximum Daily Loads (TMDLs) for impaired waters. A TMDL analyzes how much pollution a waterbody can assimilate without violating Washington State water quality standards.

The Samish River, Samish Bay, and sloughs to Samish Bay were listed by Ecology for not meeting fecal coliform bacteria (FC) criteria. The listings were based on sampling done by Ecology, the Washington State Department of Health, and the Skagit Stream Team since 1993.

Due to nonpoint (diffuse) pollution sources, FC levels did not meet freshwater quality criteria at most of the sites sampled by Ecology from 2006-07.

Data from Ecology 2006-07 field surveys showed that reductions in FC bacteria levels are necessary in the Samish River and its tributaries, in Colony Creek, and in all sloughs to the bay. These reductions are needed to protect the public from pathogens in freshwater and to protect marine water and shellfish harvesting in Samish Bay.

The goal of this study is to provide the technical analysis necessary to develop a TMDL for the Samish Bay watershed. The TMDL will be written to achieve compliance with the state′s water quality standards for FC bacteria. Identifying and eliminating sources of FC contamination in the Samish River and other tributaries to Samish Bay, as well as cleaning up the Friday Creek and Thomas Creek subbasins, will be essential for the success of the TMDL.

Link to EIM data for User Study ID TSWA0001