Restoring Pocket Estuaries Key to Puget Sound Chinook Recovery in Washington

As a tiny Puget Sound Chinook salmon fry, your job is to eat as much as possible and avoid predators. You need to grow strong so you can survive the ocean and one day return to spawn. But what if heavy flows flush you from your river into salt water before you're ready? Or, what if you can't find quality habitat in your home watershed? You cross your fins and hope you can find a pocket estuary.

Pocket estuaries are where shorelines are protected from waves, allowing salt marsh to grow, and are often fed by freshwater streams. They serve as nurseries for juvenile salmon that leave their home rivers. However, most pocket estuaries, like other salmon habitat in the Puget Sound, have been degraded and filled in for development and agriculture. This poses a serious threat to the recovery of the threatened Puget Sound Chinook.

With funding from NOAA's Office of Habitat Conservation , the Skagit River System Cooperative (SRSC) and many partners are restoring the Similk pocket estuary for Skagit River Chinook. In 2023 and 2024, the Cooperative was awarded $5.8 million through the Bipartisan Infrastructure Law and Inflation Reduction Act for salmon habitat restoration work in Washington State. NOAA has supported restoration work on the Skagit River and other locations in Puget Sound for decades.

The SRSC is a tribal natural resources consortium between the Swinomish and Sauk-Suiattle Tribes. Restoring healthy salmon populations is key to the Tribes' cultural and economic recovery. "Our ultimate goal is the recovery of a vibrant and sustainable tribal fishery and the delisting of Chinook salmon," says Colin Wahl, senior restoration ecologist for SRSC.

The Tribes historically occupied lands in the Skagit River Delta and mid and upper Skagit River. The river and its expansive estuary once teemed with Chinook salmon and other fish, which provided Tribal people with physical and spiritual sustenance.

In 1855, the Tribes ceded the lands of what would become Washington State to the U.S. government in exchange for the recognition of their reserved rights to fish in their usual and accustomed places. The government denied these rights for more than 100 years while salmon populations were exploited to the edge of extinction.

Human activities and development eliminated most of the Skagit River Delta salmon habitat, including an estimated 86 percent of the historic estuary habitat. In Puget Sound, about 400 pocket estuaries and lagoons were degraded or destroyed (PDF, 458 pages) over the last 150 years.

"The population of Chinook can't increase much because there's not enough of this estuary habitat to help the juveniles grow," says Wahl. "Lack of habitat that support juvenile development, like estuaries, are the primary bottleneck for Chinook survival and recovery identified by decades of research."

SRSC and NOAA view the restoration of pocket estuaries as essential to the recovery of Chinook. As juveniles find less space to feed and grow in the Skagit River estuary due to habitat loss, the importance of pocket estuaries has grown. Insect-eating juveniles find plenty of bugs to eat in healthy pocket estuaries. The warm brackish water aids in their dramatic metamorphosis from freshwater to saltwater fish. Juveniles are also less likely to be eaten by predators in pocket estuaries as compared to other nearshore and offshore environments.

Researchers identified 12 degraded pocket estuaries within a day's swim from the Skagit River Delta. So far, SRSC has restored three pocket estuaries and is now working to recover the Similk pocket estuary on land owned by the Swinomish Indian Tribal Community. The 17-acre Similk pocket estuary and 1,400 feet coastal stream could support roughly 8,000 Chinook smolts when restored.

Tidal exchange to Similk pocket estuary was cut off by the construction of a road and beach berm, but a freshwater drainage still exists at the site. SRSC recently completed phase 1 of the project. They worked with the tribally owned golf course on site to restore the coastal stream and protect the golf course from tidal inundation. In the next phase, SRSC will work with local governments to:

• Restore the estuary and tidal network
• Elevate a flood-prone county road
• Build a bridge over the restored tidal channel

"NOAA is eager to support habitat restoration projects that provide multiple benefits and the Similk project is a great example," says NOAA Marine Habitat Resource Specialist Laurel Jennings. "It will restore critical estuarine rearing habitat for Endangered Species Act-listed juvenile Chinook salmon during the early phases of oceanward migration. It will also build more resilient transportation infrastructure that accommodates natural nearshore processes."

Construction began in September. Crews restored the freshwater drainage from the golf course and raised the southernmost fairway about a foot to eliminate the risk of flooding. In the next few years SRSC will work with Skagit County to design and construct a new estuary channel network and road. The resulting lagoon will be inundated by the tide twice every 24 hours.

Before the current beach berm is breached to allow the tide in, SRSC will raise and rebuild Satterlee Road. This road provides the only alternative to Highway 20, which links the mainland to Fidalgo and Whidbey Island. Satterlee Road is the only alternative option when Highway 20 is closed due to an accident or flooding. And the pump that keeps Satterlee Road from flooding often fails, flooding the road. Elevating the road above sea level rise projections and building a bridge over the tidal channel will eliminate the need for a pump.

"This would provide resiliency for infrastructure, not just for the local community, but for the wider community that requires access between the mainland and Fidalgo Island," says Wahl. "This is a pretty unique project in a lot of ways, but one of the ways it's unique is that it's really just good for everybody. It's just a win-win kind of a project."

NOAA is funding the design and permitting and construction for this project. SRSC will raise additional funds to complete construction by 2026.

Additional project partners include:

• Washington Department of Fish and Wildlife
• Washington State Recreation and Conservation Office
• Swinomish Tribe
• Pacific Salmon Commission
• Skagit County

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