Publication Summary

This is the Quality Assurance Project Plan for the study, Fecal Coliform Bacteria TMDL for Oakland Bay-Hammersley Inlet and Tributaries.

Oakland Bay and Hammersley Inlet and several of its tributaries have been placed on the federal 303(d) list (1996, 1998, and proposed 2002/2004) for not meeting state water quality standard for fecal coliform bacteria. Therefore, in accordance with the Federal Clean Water Act, Total Maximum Daily Loads (TMDLs) for fecal coliform bacteria and temperature must be established to bring these tributaries into compliance with water quality standards. This report describes the approach to be used to develop TMDLs for the listed waterbodies and presents a monitoring plan to gather necessary data for completion of the TMDL.

For tributaries, a simple roll-back method will be used to establish target fecal coliform bacteria reductions necessary to meet water quality standards. Existing data, although useful, is deemed not sufficient in setting target reductions, particularly when considering different seasons. Therefore, additional data collection is proposed for a period of one year.

For Oakland Bay and Hammersley Inlet, the 303(d) listing will be addressed through a three-dimensional (3-D) hydrodynamic and water quality model. The roll-back loadings for the various tributaries, discussed above, will be used as a first cut in the 3-D model to predict if marine fecal coliform standards are met. If not, successive reductions will be assumed at the various tributaries until the marine standards are predicted to be met. Additional marine data on tides, currents, bathymetry, fecal coliform bacteria, and salinity will be collected over a year to cover all seasons.

Ecology will work cooperatively with the Squaxin Island Tribe, Department of Health, and Mason County to coordinate field work.

A final report will be available in August 2006.

Link to EIM data for User Study ID AAHM0003