The U.S. Army Corps of Engineers is seeking comments on a permit application from the Seattle Department of Transportation to repair and replace 7,112 linear feet of seawall from S. Washington Street to Broad Street along the Seattle Waterfront abutting Elliott Bay in two phases.
The replacement seawall would be constructed 10 to 15 feet behind the existing seawall and the existing seawall face would be removed. In addition to the seawall repair and replacement, habitat enhancements in the nearshore would be incorporated into the project including intertidal habitat benches, substrate enhancements, cobble reefs, wall habitat surfaces, and an intertidal beach.
Public amenities would also occur, including restoration of the Washington Street Boat Landing and installation of view decks, enhanced viewing areas, riparian planter boxes and street plantings in various locations along the seawall.
The replacement seawall would be structurally supported by means of an anchored soil improvement, which includes a jet-grouted structure to stabilize the soils behind the new seawall and anchors or tie backs that extend down to non-liquefiable soil for seismic stability as necessary.
The Corps will review the proposal as required in accordance with Section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act.
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Dredging Today Staff, June 5, 2012; Image: seattle.gov