Elliott Bay Seawall Habitat Features -- Initial Monitoring Results for Nearshore Ecosystem

The City of Seattle is completing the replacement of the Elliott Bay Seawall along its downtown urban waterfront that included the installation of numerous unique features to enhance the nearshore marine shoreline for salmon migration and to improve nearshore productivity and the food web. The urbanized waterfront is constrained by numerous large piers that shade the nearshore and adjacent deep water from a historical legacy of filling in the nearshore. Key issues addressed by the project included improving natural lighting behind and under several large piers and providing an intertidal habitat corridor along the shoreline. This presentation will describe the unique habitat features that were installed, the enhancement objectives and thresholds for success, and the results of monitoring in 2018 specific to macroalgae and invertebrate colonization and the physical stability of the installed habitat features. Initial results will be compared to pre-construction conditions with lessons learned about the effectiveness, to date, of these unique features. Monitoring will be continuing through at least 2022 and a summary of additional work will be provided. This presentation complements presentations by the University of Washington on the results of salmon migration and lighting