What's Happening Now

In 2014, EPA decided on their cleanup plan for the Duwamish. LDWG is acting now to conduct important work to advance the design of EPA's plan:

  • Enhanced Natural Recovery Activated Carbon Pilot Study - conducting a pilot study with an innovative sediment cleanup technology. Learn more >>
  • Pre-Design Studies - working with the EPA on pre-design studies to inform the cleanup.Learn more >>

Heavy equipment was used to place clean material mixed with activated carbon onto test plots at three locations along the river. For more information

The Lower Duwamish Waterway

The Lower Duwamish Waterway is a working waterway that has been a vital part of Seattle for more than 100 years. It plays an essential role in supporting commercial navigation, employment, and commerce that invigorates our economy. The waterway is also used recreationally by local residents, and is a resource for both Tribal and recreational fishing. Learn more >>

Making Progress with Early Cleanup

The Lower Duwamish Waterway Group (LDWG), a partnership between King County, the Port of Seattle, City of Seattle and The Boeing Company, has been actively cleaning up waterway pollution. These investments of nearly $200 million on studies and cleanup of 'early action' areas will reduce contamination, such as Polychlorinated biphenyls (PCBs), found in the waterway. Learn more >>

Waterway Cleanup Activities

Pre-Design Studies

LDWG is currently working with the EPA on several pre-design studies. These studies include:

  • Collecting sediment, fish and shellfish tissue, and surface water data. These data will be used to establish post-Early Action Area (EAA) cleanup conditions and serve as a baseline for future monitoring of the river wide cleanup
  • Examining how ships, barges, and tugboats and other waterway activities disturb the sediment at the bottom of the waterway.
  • Documenting structures such as piers and piling in the waterway that may affect the cleanup design.
  • Collecting sediment data to provide Ecology with additional information for source control actions.

Learn more >>

Enhanced Natural Recovery Activated Carbon Pilot Study

The LDWG partners are conducting a pilot study to determine if activated carbon, a common purifier in household water filters, traps contaminants in waterway sediments. The study is designed to see if polychlorinated biphenyls (PCBs) and other pollutants can be prevented from entering the food chain. The pollutants are trapped by activated carbon that is mixed in a thin layer of clean material (either sand or gravely sand) and placed over existing contaminated sediments. This method, if successful, could be used in the final cleanup.

The study is being carried out in three study plots on the Duwamish Waterway. The study team will monitor the plots each year for three years to determine how much carbon stays in place in different river conditions. They will also evaluate how effectively the carbon binds pollutants and make sure the carbon doesn't affect the animals that live in the mud, that make up the base of the food chain. All cleanup methods must be approved by the U.S. Environmental Protection Agency (EPA) before they can be incorporated into the cleanup plan.

Learn more >>

Fishers Study

The main way people are exposed to contamination from the Duwamish is by eating fish, crabs, and clams that are 'resident species' (those that live their entire lives in the Duwamish). As a part of the effort to reduce human exposure to contamination from the Duwamish, LDWG, EPA, and Ecology conducted a study to learn more about people who fish on the Lower Duwamish Waterway:

  • Who is fishing for and eating resident fish and shellfish from the Duwamish?
  • Why do people fish?
  • What do people know about the risks of eating resident fish and shellfish from the Duwamish?

Now that the data has been collected, EPA, county, and state public health agencies will partner with local community groups to promote healthy consumption of seafood from the Duwamish. For example, consuming non-resident fish like salmon is a better choice than eating resident fish. In addition, the Fishers Study showed that people fishing the Duwamish speak many languages and like to get information in different ways. Outreach staff will use a variety of methods and languages.

For more information: