Publication Summary

This paper presents a TMDL effectiveness monitoring strategy for Washington State. It appeared in the American Water Resources Association 2003 International Congress, Watershed Management for Water Supply Systems Conference, CD-ROM, New York, NY, June 29-July 2, 2003.

Washington State, located in the Pacific Northwest, is bounded on the north by the Canadian province of British Columbia, on the east by Idaho, on the south by Oregon, and on the west by the Pacific Ocean. The state has identified 1,317 impaired water bodies through the 1998 303(d) listing process. Washington State Department of Ecology is required, under Section 303(d) of the federal Clean Water Act and U.S. Environmental Protection Agency′s (EPA) implementing regulations, to develop and implement total maximum daily loads (TMDLs) for impaired waters, and to evaluate the effectiveness of the clean-up plan to achieve the needed improvement in water quality.

Currently, Washington State has approximately 398 EPA-approved TMDLs with impairments caused by pathogens, metals, conventional pollutants, priority pollutants, and exotic biological species. To date, TMDL effectiveness monitoring that evaluates the efficiency of the clean-up plans has been ignored. Consequently, the Washington State Department of Ecology is developing a strategy that would involve the TMDL modelers, agency planners, and local partnerships in developing and guiding implementation plans prior to initiation of effectiveness monitoring. Preliminary success for the proposed effectiveness monitoring strategy is exemplified by the Puyallup River study located in Western Washington.