Frequently Asked Questions
What is the LDW?
The Lower Duwamish Waterway represents the last five miles of the Duwamish River before it splits to flow around Harbor Island and out to Puget Sound. In the early 1900s, Seattle’s economy grew and its landscapes changed. Dredging, filling, river diversion and rechanneling supported local industries and altered the natural flow of the Duwamish to form the Lower Duwamish Waterway that we know today. In 2001, the Environmental Protection Agency (EPA) listed the Lower Duwamish Waterway as a Superfund site under federal law. LDWG is committed to advancing the EPA-led cleanup of the waterway.
What does EAA stand for?
Early Action Areas – EAAs were some of the most contaminated sediment areas of the Lower Duwamish Waterway and presented the greatest opportunities for reducing PCB contamination in the sediment. Five of the seven EAAs identified as candidates for early cleanup have already been cleaned up.
What does EPA stand for?
Environmental Protection Agency – EPA is an agency of the United States federal government. The mission of EPA is to protect human health and the environment. The EPA is the lead for the cleanup of contaminated sediment in the Lower Duwamish Waterway.
What does Ecology stand for?
Washington State Department of Ecology – Ecology is a state agency dedicated to preserving and protecting the environment in Washington. Ecology is responsible for controlling sources of pollution to the Duwamish and overseeing the cleanup of upland contaminated sites in the watershed.
What does CSO stand for and what is it?
Combined Sewer Overflows are relief points in sewer systems that carry sewage and stormwater in the same pipe. These relief points are needed to ensure there won’t be backups into homes and businesses during heavy rainfall. CSOs and stormwater runoff have in part contributed to complexity of cleaning up the Duwamish River. Learn more here.
Why hasn’t the cleanup started yet?
It has! While the sitewide studies have been happening, LDWG has invested $150 million in cleaning up 29 acres of contaminated areas. EPA’s cleanup plan covers the remainder of the cleanup actions for the 440-acre site. The cleanup is a several hundred-million-dollar effort that takes time and needs to be done right. We’re committed to supporting the EPA’s cleanup plan as efficiently as possible. We are working on the engineering design of the cleanup now. Our scientists are gathering data and our engineers are using that data to design the cleanup following EPA’s Record of Decision. The construction for the cleanup will start after engineering designs are complete.
When will final cleanup begin?
Before a final cleanup can begin, EPA and Ecology need to minimize the potential for upland sources of contamination to re-contaminate the areas that are cleaned up. While LDWG is working on the sediment cleanup design, EPA and Ecology are continuing to work on identifying and controlling potential upland contamination sources. Each of the LDWG parties also has an active role in the source control efforts. Once the design is complete and upland sources of contamination are sufficiently controlled, the parties responsible for the pollution, including LDWG, will work together to solicit bids from experienced construction contractors who will begin cleanup of the LDW.
How long will the cleanup take?
The EPA estimates that it will take at least 17 years to complete the cleanup plan (7 years of construction and active cleanup and 10 years monitoring as the rest happens naturally). We will work with the EPA and project partners to minimize impacts on our neighbors along the Duwamish during this time.
Who will pay for the cleanup?
We are working with other responsible parties to fairly divide the cleanup costs among those who contributed to the pollution over the years.
What happens after the construction?
After construction, we are required to demonstrate that we have met the cleanup objectives set in EPA’s Record of Decision – i.e., sufficiently reducing risks to human health and the environment:
- Monitor to determine if the constructed remedy is built as designed and in working order
- Correct any issues found with the construction
- Long-term monitoring to be sure the cleanup continues to be effective
- Take corrective actions if necessary
- Monitoring continues until we demonstrate that the cleanup objectives have been met.