Lower Duwamish Waterway
We are leading efforts to control sources of pollution from the drainage area surrounding the Lower Duwamish Waterway (LDW) Superfund site. The U.S. Environmental Protection Agency (EPA) oversees cleanup of the river sediments.
The LDW Superfund site is a 5-mile portion of the Duwamish River that flows northward into Elliott Bay. EPA added the LDW to the Superfund National Priorities List in 2001. We added the site to the Washington Hazardous Sites List in 2002.
Before sediment cleanup can begin, we must sufficiently control the sources of pollution to the river sediments. Source control means finding the sources and extent of contamination, then stopping or reducing them before they reach the LDW. The sediment cleanup sites are grouped together by reach (stretch of river), and the upper reach (the upstream end of the LDW) is the first on the schedule. We expect cleanup to begin in 2024.
In the summer of 2023, we submitted a report to the EPA that reviewed source control efforts in the upper reach of the LDW. Together with our source control and cleanup partners, we've made solid progress on controlling sources of pollution. We're recommending that the EPA begins cleanup at 28 out of 29 active sediment cleanup locations in the upper reach.