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Lower Duwamish River

Cutting through south Seattle, the Duwamish is an industrial river.
Cutting through south Seattle, the Duwamish is an industrial river.
A boat navigates the Lower Duwamish River with industrial development on both sides of the river's banks.
A boat navigates the Lower Duwamish River with industrial development on both sides of the river's banks.
Aerial photograph of the Lower Duwamish River. Harbor Island and Elliott Bay are shown in the top left and downtown Seattle in the top center of the photograph.
Aerial photograph of the Lower Duwamish River. Harbor Island and Elliott Bay are shown in the top left and downtown Seattle in the top center of the photograph.

Hazardous Waste Site | Washington State | Mid-20th Century

What Happened?

The Duwamish River was once a wide, meandering river with large areas of mudflats and marshes. By the 1940s, channelization and filling had transformed the 9-mile estuary into a 5-mile industrial waterway. This process destroyed 97 percent of the original habitat.

The lower Duwamish River is still highly developed, with many industrial and commercial facilities lining its banks. Hazardous substances have been released since the early 1900s, resulting in injuries to fish, birds, wildlife, and their habitats.

What Were the Impacts?

We are currently assessing impacts to:

  • Wildlife, including fish, birds, mammals.
  • Water and sediment.
  • Recreational uses, including fishing.

What’s Happening Now?

Cleanup of the Lower Duwamish River has begun, and will continue for many years. But cleanup alone will not restore the salmon and other resources that have been impacted by past contamination. In order to restore these injured resources, additional habitat must be restored. This is especially true for the survival and recovery of threatened fish species, including the Puget Sound Chinook salmon and Puget Sound Steelhead. The young of these species spend time in this part of the Duwamish River as they transition from freshwater to saltwater.

In 2013, the trustees completed a final Restoration Plan (PDF, 124 pg). In 2014, as part of a NRDA settlement, the Boeing Company constructed one of the largest restoration projects on the Lower Duwamish River—almost five acres of mudflat, marsh, and riparian vegetation, providing habitat for fish and wildlife. The company Bluefield Holdings, Inc. has also completed a restoration project and plans to sell credits derived from the project to potentially responsible parties to address injuries to natural resources. We are planning additional projects to restore mudflats, marshes, and shoreline vegetation on the river. In 2016 a workshop report was published regarding habitat lessons learned on the Lower Duwamish River (PDF, 37 pg).

On June 25, 2019 the co-trustees released the Lower Duwamish Final Injury Assessment Plan. The plan describes the Trustees’ current understanding of the Lower Duwamish River and natural resources found in the area, as well as ways to study the effects of contamination on natural resources.

The release of this plan is an important accomplishment in NOAA’s ongoing work to assess the injuries from contamination in the Lower Duwamish River.

 

Contacts

Rebecca Hoff
NOAA Office of Response and Restoration
Seattle, WA 98115
(206) 526-6276
rebecca.hoff@noaa.gov

Case Documents

Last updated July 18, 2019