Publication Summary

During 1999-2000, a Total Maximum Daily Load (TMDL) study was conducted on the lower Skokomish River and some of its tributaries. Fecal coliform bacteria targets were set in the TMDL to protect the beneficial use of shellfish harvest in Annas Bay. This attainment monitoring report determines if the TMDL targets and water quality standards for fecal coliform are now being met.

Results show that the Skokomish River at the Highway 106 bridge, Purdy Creek, and Ten Acre Creek met TMDL targets and water quality standards for fecal coliform. Weaver Creek did not meet TMDL targets but met water quality standards for fecal coliform.

The Washington State Department of 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.

The lower Skokomish River and some of its tributaries exceeded Washington State fecal coliform bacteria freshwater quality standards. During January 1999 through January 2000, a TMDL Study was conducted to (1) determine the sources of fecal coliform loading, and (2) develop load allocations that would protect water quality and shellfish harvesting use in Annas Bay.

The TMDL Study identified percent reductions needed in fecal coliform concentration and loading at four compliance sites: Weaver Creek, Ten Acre Creek, Purdy Creek, and the lower Skokomish River.

Since the TMDL, several pollution reduction actions have been implemented, including decommissioning of high-risk, on-site sewage treatment systems and installation of riparian fencing and plantings. Subsequently, a water quality Attainment Monitoring Study was conducted during 2005-2006 to determine if TMDL fecal coliform water quality targets and standards were attained for the TMDL sites sampled during this study.

This Attainment Monitoring Study showed that water quality in the Skokomish River and tributaries has improved greatly since the 1999-2000 TMDL Study. All four TMDL compliance sites have lower fecal coliform levels. All sites also met fecal coliform water quality standards during the May through February critical period.

All sites, with the exception of Weaver Creek, met TMDL fecal coliform targets during the critical period. A 20% reduction in fecal coliform levels is needed in Weaver Creek to meet the TMDL target.

Link to EIM data for User Study ID DBAT0004