habitat integration into the seattle seawall

Integrating Intertidal Habitat into Seattle’s Waterfront Seawall, Phase 2

In collaboration with the City of Seattle, investigators produced a new wildlife-friendly design for the downtown seawall, showing the way to better seawall design around the world.

Principal Investigator

Jeffery Cordell, University of Washington, School of Aquatic and Fishery Sciences

Co-Principal Investigators

John Arnseen, City of Seattle, Department of Transportation

Charles Simenstad, University of Washington, School of Aquatic and Fishery Sciences

Jason Toft, University of Washington, School of Aquatic and Fishery Sciences



Washington Sea Grant-supported scientists collaborated with the City of Seattle to design, install, and monitor large-scale test panels at three locations along the Seattle waterfront. The research compared three types of relief (flat panel, sloped steps, and a “fin” pattern resembling protruding tire treads) and two surface textures (smooth and cobbled) to untreated seawall. The first phase documented the initial response of invertebrates and algae to the different designs, and the second phase provided additional monitoring.

Research Updates


Seawalls protect urban infrastructure but degrade habitat for fish and other wildlife by transforming complex shorelines into simplified vertical walls. The replacement of Seattle’s seawall presented an opportunity to improve habitat for wildlife, including several salmon species that migrate through the area.


Second-phase results corroborated the initial findings: The relief panels (with steps and fins) supported more diverse communities than the existing seawall or flat panels. Some populations, such as mussels, reached densities on the flat panels resembling those in more natural habitats. Although initial results indicated that juvenile salmon found more prey on the relief panels, no consistent pattern emerged. As a result of this collaboration, Seattle will be the first city in the world to incorporate habitat panels into a large expanse of seawall. The city plans to monitor for several years after construction, generating the data needed to design future ecologically beneficial seawalls. More information is available at the .


Cordell J (2012) Habitat research. Interpretive panel installation, Waterfront Park, Seattle. Washington Sea Grant.

Annual Reports

2012 Final Report