Duwamish River Final Cleanup Plan

The U.S. Environmental Protection Agency has released the final cleanup plan for the Lower Duwamish Waterway Superfund site, a major industrial waterway that includes the mouth of the Duwamish River on the south end of Elliott Bay.

As part of the cleanup plan, the Washington State Department of Ecology will continue leading source control efforts that reduce incoming pollution to the river and support the EPA in-waterway cleanup.

“This is a momentous day in the history of the Duwamish River,” said Dennis McLerran, Regional Administrator for EPA Region 10. “The Duwamish serves as the region’s industrial backbone and it is home to tribes and vibrant communities. Today we celebrate the river’s history and look to a healthier future for the Duwamish with a cleanup plan that provides habitat, recreation, and a future of economic vitality.”

The cleanup plan will remove 90 percent of pollution in the river with active cleanup of 177 acres by dredging, capping, and other methods. The remaining low levels of contamination will be addressed by the river’s natural processes bringing in clean sediments to cover the contamination. The cleanup timeframe is estimated to be 17 years with an estimated cost of $342 million, with seven years of active cleanup and 10 years of natural recovery.

Industrial activity, stormwater, and combined sewer overflows have polluted the Lower Duwamish Waterway surface water and sediments over the past 100 years. Over 40 hazardous substances were found in sediments at concentrations that pose a risk to people and marine life.

Resident Duwamish fish and shellfish, which are consumed by local communities, accumulate contaminants that are harmful to human health. The primary contaminants of concern are PCBs, dioxins/furans, arsenic and carcinogenic polycyclic aromatic hydrocarbons.

As a result of early action work already underway, pollution in Duwamish surface sediments will be reduced by 50 percent in 2015. The City of Seattle, King County, the Port of Seattle, Boeing, and Earle M. Jorgensen recognized the need for a healthier Duwamish River and stepped up to do the work in parts of the river that contained the most contamination. The early action areas for cleanup are Slip 4, Terminal 117, Boeing Plant 2, Jorgensen Forge, and the Duwamish Diagonal and Norfolk combined sewer overflows.

The source control effort, coordinated by Ecology in cooperation with local governments and other parties, currently involves managing 30 state and federal cleanups along or near the waterway. In addition, Ecology is assessing pollution sources throughout the 480 square mile Green-Duwamish watershed to support and enhance the EPA in-waterway cleanup and Ecology’s source control strategy.

The cleanup also dovetails with the recently announced strategy from King County and the City of Seattle to coordinate cleanup work and enhancements across the Green/Duwamish corridor, from the Cascade Crest to Elliott Bay.

In developing the final cleanup plan, EPA engaged community members, local businesses, tribal governments and other stakeholders each step of the way. EPA considered the comments it received and incorporated changes into the final cleanup plan based on the feedback. Specifically, the final plan calls for more dredging and a commitment to work with waterway users to ensure the cleanup is compatible with all uses where possible.

The Duwamish River drains into Puget Sound, and this cleanup will add to a long line of previous cleanups that support Puget Sound protection. For Pacific Northwest tribes in particular, Puget Sound and the Duwamish River are a link to their culture, history, and tradition that goes back thousands of years.

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Press Release