Case Study: Lower Duwamish Waterway

Client: Lower Duwamish Waterway Group Location: King County (Seattle), WA Contact for environmental projects: Doug Hillman

Project Background & Challenges

The LDWG and its consultant retained Aspect to interpret hydrogeologic conditions for this Superfund Site and to assess potential impacts associated with groundwater discharge to the waterway. The LDWG consists of technical staff from the City of Seattle, King County, the Port of Seattle, and Boeing.

Solution

Building on our hydrogeologic characterization for the Duwamish Pathways Project, we evaluated contaminant migration from the major contaminated upland sites. Our work focused on understanding how groundwater and surface water interact and how constituents are transported to sediments via groundwater. The analysis indicated that, at most contaminated sites in the basin, the chemicals of concern are likely attenuated before reaching the LDW through source control and natural processes. Our analysis was well-received by the LDWG and EPA.