A view of the Duwamish Waterway from the Georgetown side of the river, near the First Avenue South bridge.
The Lower Duwamish Waterway (LDW) is a heavily developed, five-mile stretch of the Duwamish River located south of downtown Seattle. Beginning near the south end of Boeing Field (King County International Airport), the LDW flows between the Georgetown and South Park neighborhoods before it eventually empties into Elliott Bay.
Over a century of industrial use has caused the sediments in the waterway’s riverbed to be polluted with toxic chemicals. In 2001, the Environmental Protection Agency (EPA) listed the Lower Duwamish Waterway as a Superfund site, giving them oversight over the sediment cleanup.
At Ecology, our role is to stop or reduce land-based sources of pollution so that the river sediments aren’t contaminated any further. It’s not a simple task — stormwater from over 20,000 acres of land drains into the LDW, and cleaning up such a large area means we need to deal with a variety of historical and current uses and multiple property owners.
We manage over 20 formal cleanup sites in the LDW area, with many more independent sites in our Voluntary Cleanup Program. There are sites at every stage of the cleanup process, ranging from the initial assessment of contamination and risks to human and environmental health, through more detailed investigations and project design, to final cleanup and monitoring.
This fall, we have two sites in the LDW area that are reaching different stages of the cleanup process, and we’re asking for your input.
Independent Metals
Located in the South Park neighborhood, the Independent Metals site covers three acres along the Lower Duwamish Waterway, in the area bounded roughly by South Kenyon Street, South Chicago Street, and 8th Avenue South. It’s made up of multiple tax parcels and a portion of public right-of-way.
The site has seen a number of land uses over the past century. Previous businesses on the site included a gas station and a boat manufacturer. More recently, Independent Metals ran a scrap and recycled metal operation on the site between 2006 and 2014, and between 1996 and 2015 Silver Bay Logging used the site to transfer processed logs.
Based on early investigations, we determined that the site has soil contaminated with:
- Diesel and oil-range total petroleum hydrocarbons (TPH)
- Carcinogenic polycyclic aromatic hydrocarbons (cPAHs)
- Tetrachloroethene (PCE)
- Trichloroethene (TCE)
- Polychlorinated biphenyls (PCBs)
- Metals, including arsenic, cadmium, and lead
We’d like your input on two documents:
- Agreed Order. This is a legal agreement we’ve negotiated with the potentially liable persons. They will be required to investigate environmental conditions, identify alternatives for cleaning up the site, and write a draft Cleanup Action Plan.
- Public Participation Plan. This is Ecology’s plan for informing and involving the community during the cleanup process.
The public comment period will run Oct. 24 – Nov. 22, 2022. During that time, you’ll be able to submit comments either through an online form or by email to LDW@ecy.wa.gov.
We’re also holding an online public meeting on Wednesday, Oct. 26, beginning with a presentation from 6:30 – 7:30 p.m., followed by a question and answer session.
Spanish, Chinese, Vietnamese, and Khmer interpreters will be available. Visit our meeting registration page for more details.
North Boeing Field – Georgetown Steam Plant
North Boeing Field – Georgetown Steam Plant is a 116-acre site sandwiched between Boeing Field and East Marginal Way S, in Seattle’s Georgetown neighborhood. The overall site is still being evaluated for where contamination needs to be addressed and the best ways to clean it up.
In the meantime, we’d like your input on the proposed plan for about an acre of the northwest corner of this site, where the City of Seattle plans to build an off-leash dog park and walking/bicycling trail.
The dog park project area is part of the former location of the Georgetown Steam Plant’s flume, which carried water between the plant and the Duwamish Waterway. The flume was removed in 2009 and this area is currently undeveloped, with vegetation, bare dirt, and gravel. Possible contaminants in the soil include polychlorinated biphenyls (PCBs), carcinogenic polycyclic aromatic hydrocarbons (cPAHs), and metals.
To get the project area ready to be used as a dog park and trail, the City of Seattle is proposing to remove the top layer of soil, to a depth of 1-2.5 feet, and replace it with clean fill.
We invite your comments on:
- Interim Action Work Plan. This work plan describes the cleanup of contaminated soils on the project area.
- State Environmental Policy Act (SEPA) Determination of Non-Significance. This is our determination that this work is not likely to harm the environment.
The public comment period will run Nov. 7 – Dec. 21, 2022. During that time, you’ll be able to submit comments either through an online form or by email to julia.schwarz@ecy.wa.gov .
We’re also holding an online public meeting on Wednesday, Nov. 9, beginning with a presentation from 6:30 – 7:30 p.m., followed by a question and answer session. Spanish, Chinese, Vietnamese, and Khmer interpreters will be available. Visit our meeting registration page for more details.