Seattle's New Seawall: An Experiment in Climate Adaptation and Habitat Restoration

Ken Christensen tells the story of Seattle's new $140 million seawall—an underappreciated but critical piece of infrastructure.

Christensen describes the seawall as an ongoing experiment in habitat restoration, in addition to the brute strength it provides to keep the rising tides at bay. Jeff Cordell, a fish biologist at the University of Washington, is quoted in the article saying the new Alaskan Way seawall is the first of its scale to try to improve habitat for fish.

For 80 years, the Alaskan Way seawall was like most: a smooth, vertical slab of concrete that held back the sea for the city’s bustling waterfront. It helped cement Seattle’s status as a commercial hub and deepwater port, but also sealed the fate of salmon habitat, locking away miles of gradually sloping beaches.

Now:

The new seawall should make life easier by featuring an underwater corridor for the fish to pass through on their way to the ocean. It’s illuminated by glass tiles in the pedestrian sidewalk above and filled with rocky surfaces where microalgae and small marine invertebrates are more likely to survive.

In the early days of the new seawall, the project shows promise, as filamentous microalgae has begun to show at low tide, which will make the new sea wall a more attractive environment for fish. If the experiment is successful, the new seawall could be a model for other coastal communities around the world, faced with the prospects of rising sea levels as a result of climate change.