Seawall

Before the Elliott Bay Seawall Project, the waterfront had many types of seawalls that were built before 1934. These seawalls had protected Seattle for more than 70 years, but time and the harsh marine environment weakened their structures.  

In 2017, the City of Seattle replaced a portion of the seawall between S Washington St on the south and Virginia St on the north. This new section is built to last over 75 years and improve the lost nearshore environment. 

The new seawall serves as the foundation for Seattle's new waterfront.  It is stronger and has been built to meet earthquake safety standards, while also creating a much better habitat that supports the ecosystem's health and restores salmon migration.

Award Winning

The Elliott Bay Seawall project received the American Public Works Association's Washington State Chapter 2017 Disaster or Emergency Construction/Repair Project of the Year Award, Advancing Women in Transportation Puget Sound Chapter’s 2017 Transportation Innovative Solutions award, and the American Council of Engineering Companies’ Washington Chapter 2017 Platinum Award for Environmental Design.

Project Gallery

A view of the seawall showing vegetation growing on it Seawall face showing lines of high tide and mean tide Getting sunlight to the water is important for encouraging habitat growth and lighting the way for migrating salmon The old sidewalk was replaced with light-penetrating surfaces that allow natural sunlight through to the water below The first step to rebuilding the seawall was removing the sidewalk and installing sheet pile Then we excavated to the old seawall's relieving platform Installing jet grout into the soil Then we poured concrete slabs Installing textured face panels, habitat benches, and marine mattresses Installing zee panels

Habitat Improvements

When Seattle's existing waterfront was developed, Elliott Bay lost many of its natural habitat features for fish, including sloping beaches, crevices and vegetated hiding places for salmon. Seattle's new seawall was built to improve marine habitats, with a special focus on encouraging juvenile salmon migration. The new seawall face includes grooves and nooks to promote algae growth, rock beds in the bay floor for fish to hide and forage in and a light-penetrating surface in the sidewalk above to provide light for young salmon during their migration.

The city hired researchers from the University of Washington's School of Aquatic and Fishery Sciences to monitor the results of the habitat improvements since the seawall was completed in 2017. Our 2018 monitoring report spotted 10,000 juvenile salmon in a single day in May.

Graphic showing the layers of the Seawall: the first is a light penetrating surface, then a zee panel that allows space for habitat, a face panel that incorporates texture, a habitat shelf that allows for vegetation to grow and a marine mattress that created shallower water

Art - Seawall Strata

View of the texture of Seawall Strata and the light diffusing panels above bringing light into the area

The wall texture emulates the life forms it is trying to attract. Enlarged geometric renditions of barnacles, mussels, anemone, starfish, and rockweed are arranged vertically in rough alignment with where they live within the intertidal zone of Elliott Bay. Eventually the concrete will be obscured by these and other life forms.

The seawall is at the dynamic seam between land and sea where a myriad of elements interact in complex ways. A primary goal of the seawall replacement project was to increase habitat along this dynamic edge. 

Titled Seawall Strata, the artwork was developed by Laura Haddad and Tom Drugan. Haddad|Drugan used concepts of biomimicry to conceive a concrete texture for the seawall, with a goal of enhancing the growth of marine life.

As part of their collaboration with the Seawall design team to develop its Art Programming Plan, Haddad|Drugan worked with engineers and aquatic scientists to develop a texture for the concrete seawall face panels, with a goal of improving ecosystem functions along this edge.