East Waterway Sediment Cleanup

Westward view of Harbor Island with port operations, storage fuel tanks and various buildings and equipment at sunset.
Aerial photo of Harbor Island and the East Waterway taken in 2012.

Project Description

The East Waterway is a one mile long, 157 acre portion of the United States Environmental Protection Agency’s (EPA) Harbor Island Superfund Site. The United State Environmental Protection Agency (EPA) is overseeing the cleanup of the East Waterway to remove and remediate historical contaminants that threaten human and environmental health. The East Waterway Group (EWG) (the City of Seattle, King County and the Port of Seattle) work together to collect data and design a cleanup. EWG is committed to effective and timely cleanup of the East Waterway to improve public health and protect the environment.

Information about this project is available at the East Waterway Group website. 

Map with the Harbor island Superfund Site, the East Waterway, and the Lower Duwamish Waterway Superfund Site.
East Waterway Cleanup Location. Credit: Port of Seattle.

Location

The East Waterway, located at the mouth of the Duwamish River, is along the east side of Harbor Island.

What’s happening now

In May 2024, EPA issued their draft cleanup plan (also known as an Interim Record of Decision) detailing the EPA’s chosen remedy for the East Waterway. Currently scientists and engineers are collecting data to refine which areas need cleanup and which technologies to use for cleanup.

Background

The East Waterway contains historical pollution from industrial and urban use. Sediment contamination in the East Waterway (PCBs, arsenic, dioxin/furans, and PAHs) pose risk to people and the environment.

On September 23, 2021, the City of Seattle, King County, and the Port of Seattle sent a letter to EPA about the Lower Duwamish Waterway and East Waterway cleanup plans and our continued dedication to reducing unacceptable risks to human health and the environment. View the EPA letter in full (PDF).

In April 2023, EPA presented a proposed cleanup plan. In May 2024, EPA issued their final cleanup plan detailing the EPA’s chosen remedy for the East Waterway. These plans and a summary of EPA’s responses to public comments are available on EPA’s website.

Learn more about United States Environmental Protection Agency’s (EPA) oversight of East Waterway cleanup: EPA and East Waterway.

Lower Duwamish Waterway and the East Waterway

The Lower Duwamish Waterway and the East Waterway are economically, ecologically, and culturally significant for the residents of Seattle. More than a century of urbanization and industrial activity polluted the sediments in both waterways, posing risks to people and the environment, and prompted the U.S. Environmental Protection Agency (EPA) to list both areas as Superfund sites.

Though the two waterways are physically connected, they are two separate, active cleanup projects led by the EPA. The City of Seattle is involved with two separate working groups that have collaborated to fund and clean up these contaminated waterways.

Map of Duwamish Superfund site.
View the enlarged Duwamish Superfund Project map. (PDF)

Learn more about EPA and Washington Department of Ecology's (DOE) oversight of Lower Duwamish Waterway cleanup:

Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000
SPUCustomerService@seattle.gov

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Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.