Cecil Moses Park Estuary Development King County Department of Natural Resources
HWA GeoSciences Inc. provided geotechnical engineering services for development of an estuary on the lower Duwamish Waterway. This estuary is unique in that it will be one of the first projects to be done entirely for restoration of the lower Duwamish. Typically these types of projects are done as mitigation for a take of wetland elsewhere. This project is also unique in that the proposed estuary will require excavation near an existing water main. HWA determined that during a seismic event, the side slopes of the estuary could fail and would rupture the water main. In order to protect the water main, HWA designed a buttress of stone columns to be installed between the water main and encroaching partially down the side slope of the estuary. This buttress will not only replaced poor soil with better quality rock, but will also densify the soil to minimize liquefaction potential along the edge of the estuary and the water main.
Other Notable Projects:
Chinese Reconciliation Park City of Tacoma
Gas Works Park Restoration City of Seattle
Burke-Gilman Trail Slides King County Department of Natural Resources
East Lake Sammamish Trail King County Department of Natural Resources
Puyallup River Trail, Phase 1 Pierce County Public Works Department
North Creek Trail, Phase 1A City of Bothell and City of Everett
HWA GeoSciences Inc. provided geotechnical engineering services for development of an estuary on the lower Duwamish Waterway. This estuary is unique in that it will be one of the first projects to be done entirely for restoration of the lower Duwamish. Typically these types of projects are done as mitigation for a take of wetland elsewhere. This project is also unique in that the proposed estuary will require excavation near an existing water main. HWA determined that during a seismic event, the side slopes of the estuary could fail and would rupture the water main. In order to protect the water main, HWA designed a buttress of stone columns to be installed between the water main and encroaching partially down the side slope of the estuary. This buttress will not only replaced poor soil with better quality rock, but will also densify the soil to minimize liquefaction potential along the edge of the estuary and the water main.