Hood Canal Bridge fish passage study receives $3.6 million in state funding

Posted

Funding to continue studying the effects of the Hood Canal Bridge on migrating fish has been included in the Legislature’s recently passed state budget.

The Hood Canal Steelhead Project, spearheaded by Long Live the Kings — a nonprofit that targets the restoration of wild salmon populations and advocates for sustainable fishing practices in the Pacific Northwest — has received $3.6 million to further study how structures installed at the bridge can assist steelhead migrating past the bridge and limit the number of fish killed.

“This will allow us to test fish passage devices at the bridge,” said Lucas Hall, senior project manager with Long Live the Kings.

“We intend for these devices to be in the water by spring of 2022 and they will be in the water from the approximate time of the steelhead out-migration, which is April through June,” he said.

The temporary fish passage structures would be installed in a manner that would allow for experimenting to see how fish respond to the structures when they’re installed versus when they’re not.

A six-year study, completed in September 2020, found that about half of juvenile steelhead trout are unable to get past the Hood Canal Bridge during their migration.

The study identified a number of factors as contributing to their inability to find their way through, including predation by mammals capitalizing on the migratory slowdown created by the bridge.

The bridge structure itself also has been shown to prevent fish passage, as well.

The study observed juvenile fish apparently becoming disoriented and inadvertently getting turned around after following 90-degree corners of the bridge’s concrete pontoon sections.

With the caveat that the group is still in the planning process, Hall said the idea is to utilize large inflatable bags which will span diagonally across the bridge’s hard corners to help encourage fish to pass through the problem areas without getting turned around.

Initially, the plan was to utilize nets to block the sections, but Hall noted that nets posed a potential hazard for entanglement of sea mammals and other wildlife.

“We’re currently still in the design process,” Hall said. “We’re basically reconciling the amount of funding we got from the state Legislature with refined cost estimates.”

Hall also noted that while
$3.6 million is a significant windfall for the study, the funding is not as much as it seems, especially when it comes to building the fish passage devices and doing work on the Hood Canal Bridge.

“We were surprised at some of the cost estimates,” he said of the fish passage devices. “The fact of the matter is these are fairly large objects and they’re custom built.”

“The solutions we’re pioneering here are pretty cutting-edge. But man, I wish they were cheaper,” Hall explained. “I was talking with a bridge engineer at WSDOT and he just said, ‘Nothing’s cheap on the Hood Canal Bridge.’ So, it is what it is.”   

The data gathered by the study could also serve to help understand how populations of Chinook and chum salmon are affected by the bridge.

Despite anecdotal evidence suggesting that juvenile Chinook and chum salmon are not making it past the bridge, technological limitations in the group’s telemetry systems makes tracking them unfeasible.

“The problem is, it’s one thing to know that juvenile Chinook and chum are dying at the bridge ... Our task is to test the hypothesis that mortality at the bridge is disproportionately higher than it would be otherwise. That’s the question that’s difficult to answer.”

While the group’s data-gathering technology makes observing young salmonids tricky, the limitations do not remain true for the returning adults.

With this next round of funding, Hall said the group would track some of the returning fall chum salmon and possibly even some returning Chinook.

Hall said the study at the bridge has unveiled impacts to local wildlife previously left unconsidered.

“This is a prime example of how our built environment can impact the natural environment in unique ways that we never thought were possible,” Hall said.

“To address them is going to take quite a bit of effort. This is by no means going to be solved with this round of solutions or alternatives to mitigate mortality. The assessment stated that it was likely that a new bridge would be required to completely address mortality.”

For the project’s continued funding, Hall thanked legislators with Washington’s 23rd, 24th, and 35th districts, calling them “Instrumental in getting this funding.”

“I think that they really deserve a shout out for prioritizing the local environment and infrastructure investments in their local communities,” he said.