Riverton Creek Flap Gate Removal Tukwila, Washington

To provide a more natural open discharge and eliminate a fish barrier from the outfall of Riverton Creek into the Duwamish River, associated flap gates and pipe culverts would need to be removed.

Improved Fish Passage and Pedestrian Bridge

Incorporated into the work was the design of a bridge to carry the Green River Trail over the new Riverton Creek channel. Improvements also include the removal of a portion of an existing concrete retaining wall and of retrofit an existing sheet pile wall that supports Pacific Highway South using soil anchors. Design of a new deep retaining wall supports a private parking lot. Included in stream enhancements was a focus on riparian plantings. In addition to executing the project, the Otak team led updates to previously provided reports and developing plan, specification and estimates (PS&E).