Urban Estuary Restoration

Can blue-green infrastructure approaches create functional estuary habitat for salmon in urban waterways?

Project Overview

Long Live the Kings (LLTK) is leading a new partnership with Vigor and the University of Washington (UW)’s Wetland Ecosystem Team to restore habitat along the Harbor Island shoreline within the Duwamish estuary. This project will evaluate the effectiveness of a blue-green infrastructure approach to create functional estuary habitat for juvenile salmon along working shorelines. The partnership between LLTK, Vigor, and UW exemplifies collaboration across sectors to support the economy and environment. Lessons learned from this project can support future restoration projects within urban waterways.

The Problem

Working waterfronts and waterways are essential components of our economy and are fundamental to our regional identity, but we must develop better ways to integrate these needs with the needs of our natural environment. The Duwamish estuary is an important waterway for many businesses along Harbor Island and the Duwamish River. The estuary also provides vital habitat for outmigrating juvenile salmon. However, over the past century of urban industrialization, the Duwamish estuary has lost 97% of the habitat it once provided these fish.

LLTK’s Salish Sea Marine Survival Project (SSMSP) showed that healthy estuaries are a critical need for young Chinook salmon: without functional estuary habitat, small salmon are less likely to survive to adulthood. Wild salmon – including Chinook, chum, and steelhead – are listed as threatened under the Endangered Species Act, making salmon recovery a priority throughout Puget Sound. In the Duwamish estuary, cross-sector collaboration is required to effectively evaluate blue- green infrastructure approaches to restoring habitat and recovering salmon populations.

Our Solution

To mitigate the impacts of a working shoreline, Vigor engaged LLTK and UW’s Wetland Ecosystem Team to initiate a restoration project with the goal of creating much-needed functional estuary habitat for juvenile salmon. A team of LLTK and UW scientists will develop a before-restoration baseline by sampling fish and insects at the restoration site and a nearby site with natural shoreline (the “reference site”). Sampling will occur throughout the juvenile salmon outmigration, when estuary habitat plays an essential role in their survival. Once Vigor’s team completes their restoration work, scientists will measure improvements in habitat function, showing before-after comparisons of shoreline vegetation, insect abundance, and presence and feeding of fish in the newly restored intertidal area relative to the reference site.

The before-after comparison will provide insight into whether blue-green infrastructure approaches are an effective technique for creating functional estuary habitat along working shorelines. If so, Vigor and LLTK plan to promote the effort and support other businesses and land owners interested in adopting similar restoration projects to maximize impact and support salmon recovery.

View an information sheet about the project here.

Project Impact

TBD

Species Impacted

2.64

Acres of Habitat

$463,000

Monitoring cost

5

Years of Monitoring

Project Partners

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Project Contact

Iris Kemp

Senior Project Manager

206.382.9555, x24 ikemp@lltk.org