Source control areas

We have defined 24 source control areas around the Lower Duwamish Waterway. We work with the Source Control Work Group to control pollution sources like contaminated sites, stormwater, and combined sewer overflows within these areas.

We developed a Source Control Action Plan (SCAP) for each source control area. Each SCAP identifies potential contaminant sources and ways they may reach sediments. The plan evaluates the significance of these sources and their potential for recontaminating sediments, and identifies actions needed to control them. It also describes sampling and monitoring that will be conducted to identify any additional sources.

The Source Control Action Plan Handbook explains how we developed the SCAPs and why there are differences between earlier and later SCAPs and associated reports. It also discusses some of the challenges that were encountered during this process.

Below the map you can find the SCAP and related documents for each area. The Combined Sewer Overflow (CSO) Basins are being addressed under King County’s and City of Seattle’s CSO Control Plans.

Click within a source control area for more information, or read below.

East of the Lower Duwamish Waterway

West of the Lower Duwamish Waterway