Knowing the value of restoring the Duckabush Estuary

Washington Department of Fish and Wildlife (WDFW) and a suite of partners have known for years that restoring the Duckabush Estuary in Jefferson County is critically important. A new Earth Economics report commissioned by the Hood Canal Salmon Enhancement Group confirms just that, estimating the area’s restoration would protect and generate up to $250 million in benefits over the 100-year life of the estuary’s bridge.

For almost a century, a 10-foot-high wall of fill dirt — measuring about 30,000 cubic yards, or enough to fill about nine Olympic-sized swimming pools — has supported Highway 101 and stretched across the Duckabush Estuary, substantially blocking the estuary’s natural connection to nearby tidelands and confining the river to two defined channels.

View of Duckabush estuary restoration site. Photo courtesy of John Gussman.

WDFW, in partnership with the U.S. Army Corps of Engineers (Corps) and the Hood Canal Salmon Enhancement Group (HCSEG), is leading a restoration project on the Duckabush River estuary in Jefferson County that would replace Highway 101 and tens of thousands of cubic yards of levee and roadway that constrict water movement. With federal Corps funding as well as funding that WDFW is requesting from the 2023 Legislature, the project would reconnect the Duckabush River to neighboring floodplains and wetlands by modifying local roads and elevating Highway 101 onto a bridge and restoring a more natural topography. The bridge would span the estuary, the area where freshwater from the Duckabush River meets the saltwater of Hood Canal. Estuaries throughout Puget Sound provide unique, rich habitat to many species that have important cultural, commercial, and recreational value.

Released this winter, “The Economic Impact of Restoring the Duckabush Estuary” by Earth Economics assessed the economic value the project would create and protect, including the estimated the number of jobs the project would support in the surrounding community. The report also estimated the value of the economic benefits that nature provides for humans, known as ecosystem services, including clean air and water, habitat for fish and wildlife, flood risk, education, and recreational value.

Climate resiliency

Flooding affects traffic and properties in many coastal areas and sea level rise and changing weather patterns are likely to make the issue more problematic in the future.

• Flood risk reduction — The new bridge is engineered to pass 100-year river flood events and account for projected sea-level rise, providing a benefit of $897 per year in avoided flood damage to nearby residents.
• Avoided road closures — Raising the road profile of Highway 101 would reduce maintenance costs by $8,000-$54,000 over the lifespan of the bridge.
• Stormwater management — The project includes three channels designed to manage and filter stormwater. Earth Economics valued the contribution of the bioswales in terms of reduced stormwater management costs as $3,600 to $4,100 annually.

Social benefits

The project is anticipated to bring an additional suite of benefits for Washingtonians’ quality of life.

• Ongoing stewardship — Volunteers have participated in programs monitoring birds, vegetation, water quality, and sediment since 2018. They are expected to continue for five years post-construction. The total value of volunteer time is estimated at $60,000.
• Aesthetic benefits for area residents— It’s hard to put a value on people’s appreciation of the scenery, sounds, and smells of nature. Homes are often higher in value the closer they are to natural amenities. The report valued the aesthetic benefit of the estuary at $27.5 million to $84.49 million for area residents and visitors over the lifetime of the bridge.
• The value of outdoor recreation— The Duckabush Estuary provides waterfowl hunting, angling, and wildlife watching opportunities as well as sightseeing, picnicking, photography, and more. Recreation provides an estimated $4.9 million to $15.1 million in benefits to estuary users during the bridge’s lifetime.
• Living-wage jobs — The report anticipates the project would create nearly 500 jobs annually over the 5 years of construction, representing about 1.54% of Jefferson County’s employable population.

Environmental benefits

Over the bridge’s lifespan, the report estimated the following benefits:

• Carbon sequestration — Natural lands can remove atmospheric carbon dioxide — a greenhouse gas — contributing to increased climate stability. Through carbon sequestration, nature provides benefits by reducing the damage of greenhouse gases — such as impacts to human health and increased natural disaster risk. The Duckabush Estuary is estimated to provide $577,000 to $1.7 million in climate stability benefits.
• Wildlife habitat— The estuary provides shelter for wildlife, promoting growth of species and maintaining biological diversity. Elk visit the area to graze, and other wildlife such as eagles are frequent visitors. Habitat was valued at $6.7 million to $20.6 million.
• Chum salmon — Restoration could result in up to 4,300 additional returning adults each year, almost double the current smolt-to-adult return rate. Over 100 years, this will total an additional 400,000 fish. The report estimates increased chum salmon would be worth $29.5 million to $108.9 million to residents of the Puget Sound.
• Improved water quality — Natural wetlands help maintain good water quality by processing and removing contaminants from the water — benefitting both human and wildlife. This natural filtration was valued at $4.4 million to $13.6 million.

These are just some of the benefits the report assessed and valued, and researchers indicated the total ecosystem service value could be much higher.

The Duckabush Estuary habitat restoration project is an example of projects underway through the Puget Sound Nearshore Ecosystem Restoration Project. The program has invested over $20 million to study Puget Sound’s 2,500 miles of shoreline and identify opportunities for large-scale habitat restoration. As outlined in the referenced Earth Economics report, restoring shoreline habitat has long-lasting benefits for a variety of native plant and animal species and contributes to a sustainable economy.

More information about the Duckabush Estuary project is available on WDFW’s website. Restoration activities are primarily on public land at the Duckabush Wildlife Area Unit managed by WDFW. Project design is expected to be complete in 2023. Once construction funding is secured, construction would take about four years.

To reference the full report, visit Hood Canal Salmon Enhancement Group’s website.