Publication Summary

The Willapa River and several tributaries are on the 1998 303(d) list of impaired waterbodies due to violations of one or more Washington State water quality criteria. Results from this study will verify where the river meets standards. The data will be used to help focus local efforts on areas where bacteria problems continue to exist. Results show that most of the sampling stations met both water quality criteria for fecal coliform bacteria; however, several stations exceeded the second part of the water quality standard. Nine of the 24 stations sampled did not meet standards.

The Washington State Department of Ecology is required, under Section 303(d) of the federal Clean Water Act and U.S. Environmental Protection Agency (EPA) regulations, to (1) develop and implement Total Maximum Daily Loads (TMDLs) for impaired waters, and (2) evaluate the effectiveness of the water cleanup plan to achieve the needed improvement in water quality.

The Willapa River and several tributaries are on the 1998 303(d) list of impaired waterbodies due to violations of one or more Washington State water quality criteria. The mainstem and several tributaries exceed (do not meet) the water quality criteria for fecal coliform bacteria, dissolved oxygen, and temperature. The EPA requires states to develop and implement cleanup programs through the development of TMDLs for listed parameters and to periodically monitor progress toward compliance with TMDL targets.

This assessment verifies current conditions and compares the data with results from previous studies conducted since 1997. Fecal coliform concentrations during a 1997-98 study by Ecology found that only five of 30 sites sampled met Washington State water quality standards for fecal coliform bacteria. 2004 data show that conditions improved significantly in many parts of the basin, especially in the lower stretch of the river. Results from this 2006 study verify where the river meets standards. The data will be used to help focus local efforts on areas where bacteria problems continue to exist.

The objectives of the study are to: (1) clarify general areas of fecal coliform bacteria pollution and compare current conditions to Washington State water quality criteria for fecal coliform bacteria, (2) compare current and previous monitoring data to determine direction of change, and (3) provide data for TMDL revision and for decisions on local TMDL implementation planning/responses.

Most of the sampling stations met both water quality criteria for fecal coliform bacteria; however, several stations exceeded the second part of the water quality standard. Nine of the 24 stations sampled did not meet standards.

Link to EIM data for User Study ID OGEO0001