Restoring Snohomish estuary habitat to improve salmon survival

Where the Snohomish River meets the saltwater of north Puget Sound, the recently completed Blue Heron Slough project was the push that brought estuary restoration by acreage above the 10-year goal—of 1,237 acres—set in the 2005 Snohomish River Basin Salmon Conservation Plan.

Despite being several years behind deadline, the 353-acre project completed in 2022 is a piece of the puzzle to bring salmon back to the Snohomish River watershed in higher numbers, and to sustain them through a changing climate.

Tulalip Tribes member Daryl Williams toured the Blue Heron Slough restoration project in the Snohomish River estuary by boat in November 2022.

For years, the Tulalip Tribes have focused on restoring habitat in the estuary where the river meets Port Gardner and Port Susan bays, particularly because of the value of those habitats in supporting threatened chinook salmon.

The Tulalip Tribes played a key role in advancing the Blue Heron restoration to mitigate for industrial pollution in Port Gardner Bay, and now hold a conservation easement on the site.

“We’re creating a much better environment for the fish to use and feed before going to Puget Sound and eventually the ocean,” said tribal member and environmental liaison Daryl Williams. “The bigger the fish are when they head out to sea, the better their chances of survival.”

The Blue Heron Slough site is adjacent to the tribes’ Qwuloolt Estuary restoration project, the county-led Smith Island restoration project and other protected areas in the estuary.

“It helps connect a variety of other projects that have recently been completed and creates continuity in the Snohomish Estuary,” said the tribes’ restoration, acquisition and stewardship senior scientist Brett Shattuck.

The Blue Heron Slough project site is shown in green on this map from a 2019 report. The Qwuloolt project is the blue section marked No. 1.

The tribes, in partnership with Snohomish County, NOAA Fisheries and others, help monitor this growing estuary restoration network. The results so far are promising.

“We are seeing pretty immediate use of chinook in these habitats and we are hoping to see increases in abundance over time,” Shattuck said, adding that DNA testing has shown fish from other watersheds, including the Skagit and Stillaguamish rivers, are also using the habitat. “We’ve all been able to work together to fit the puzzle pieces together. We’re not done yet, but what has been done, it’s working for fish.”

The effort has been a long game, with the 400-acre Qwuloolt project, for example, taking about 20 years and $20 million to complete.

“Since the levee breached in the Qwuloolt estuary we’ve seen a dramatic shift in the species assemblages and habitat quality that is much more beneficial for native fish,” Shattuck said. “Before restoration the whole site was basically covered in nonnative, invasive reed canary grass. All of that reed canary grass died and was replaced by a variety of native plants.”

The shift in plant growth has supported fish and wildlife including a growing variety of birds, from bald eagles and great blue herons to ducks, geese and songbirds.

“Pre-project we had warmer water and invasive species like black crappie and bass,” said Todd Zackey, marine and nearshore program manager for the tribes. “Since the project, we are seeing few invasive fish and instead more native fish, including chinook salmon, moving into the Qwuloolt project channels.”

Heron Point in the Snohomish River estuary boasts mature waterfront forest; the type of habitat the Tulalip Tribes hope to see develop at area restoration sites.

The Tulalip Tribes hope to see that habitat continue to evolve, eventually into mature waterfront forest like seen at Heron Point, another site that the tribe recently purchased to preserve.

“This is what the whole area used to look like,” Zackey said. “This is ideal habitat. There’s more water, more bugs, more places for fish to hide.”

So while the Blue Heron Slough project marked a delayed milestone toward salmon recovery in the Snohomish River watershed, in some ways the work is just getting started.

“We’ve done a lot of good work in the estuary, but it’s just the beginning,” Williams said. “If we’re going to recover salmon, we have to do all of it.”

At top: Equipment is staged at the site of the most recent salmon habitat restoration project in the Snohomish River estuary, at Blue Heron Slough. Photos and story: Kimberly Cauvel