Duwamish Gardens Restoration Design

CLIENT City of Tukwila

Location Tukwila, WA

The Duwamish Gardens project restored a former industrial farm site into a 10-acre brackish tidal marsh on the Duwamish (Lower Green) River.

Photo Credit: Drew Coombs

The project involved tidal marsh design, tidal hydrology modeling, geotechnical slope protection design, evaluation of spring juvenile Chinook rearing and use, cultural and archaeological resource characterization, and contaminated soils remediation. The project also required excavating and removing a layer of contaminated soils, followed by excavation and dewatering down to the target marsh plain and mudflat elevations.

Shannon & Wilson's design team roles included hydrologic/ hydraulic modeling and sediment transport analysis, contaminated soils studies and design, geotechnical engineering studies and design, and cross-coordinating the subsurface investigation study with the project archaeologist. We also helped facilitate additional project scoping and coordinated with the City of Tukwila and the Salmon Recovery Funding Board to acquire additional funding to fully complete geotechnical, contaminated soils, and archaeology studies, which were under-scoped and underfunded in the original project grant.


Scott Gaulke
Vice President

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