For beavers, tall dams don’t always make good neighbors

ARLINGTON — The waters of Twin Lakes had risen several feet in the span of just a week.

The boat docks that normally offered fishing access for visitors to the Jim Creek Recreation Area were fully underwater. A parking lot near the lake had already flooded. And the levels were only continuing to rise, creeping steadily toward the little boathouse on the shore.

Given that in mid-October the area had been suffering a monthslong drought, this was unusual, to say the least. So Naval Station Everett, which owns the recreation area about 11 miles east of Arlington, set out to find out why.

It wasn’t difficult for Alicia Higgs, the station’s natural resources manager, to determine the cause. A family of beavers had set up camp in the drainage between the two lakes and gotten as busy as, well, beavers in building a dam to call home.

It’s not the first time the Jim Creek location — home to a Navy radio station and a camping-and-recreation site for military members — has dealt with beaver-caused backups, Higgs said. In the past, the station might have turned to destroying dams to resolve the blockages. In other places, Higgs said, resource managers sometimes order lethal removal of beavers. But Higgs had a better idea, one that could keep the beavers happily munching wood away from the flooded lakes and benefit an ecosystem in need, too.

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She reached out to the Tulalip Tribes. Since 2014, the Tulalip Beaver Project has relocated “nuisance” beavers to strategically chosen spots in the upper Snohomish watershed. Dylan Collins, assistant wildlife biologist for the Tribes, said the transplanted beavers can then serve an important purpose: restoring critical salmon habitat.

When beavers start building in spots where water flow is low due to drought or human impediments, Collins said, the dams that caused problems in the beavers’ former homes help to create the clear, cold streams needed for salmon to thrive. A 2019 study showed each beaver relocated by the Tulalip project created about 2,600 square feet of surface water storage.

“It really comes down to the system that we are living in,” Collins said. “Salmon and beavers have coexisted for thousands of years, and dams in those natural systems rarely impede salmon migration, but that isn’t always the case in human-created systems.”

Collins said the majority of removals performed by the project are in urban or suburban areas where beavers have set up shop in ditches or streams. These steep-sided, shallow waterways aren’t like the rivers where the critters might normally build a dam. Collins said dams here can be up to 7 feet tall and have almost no water passing under them, creating an “unnatural” blockage for fish and, often, flooding in their human neighbors’ yards and homes.

This wasn’t the case for the dams causing trouble at Twin Lakes — the beavers had just picked a rather inconvenient spot. Regardless, the Navy needed to send them packing.

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To reach the problematic dam, Collins’ team would have needed to hike about half a mile on foot. That would become an issue when they hauled back 25-pound traps with 70-pound adult beavers inside, so they paddled out in a boat. Hancock traps, suitcase-like contraptions that enclose beavers like a clamshell when they swim over a trigger, were set in strategic areas around the dam. As beavers were caught, the team picked them up and brought them to a holding facility where they awaited the rest of their family group.

It took about a week before the whole beaver family, two adults and three juveniles, were all caught. Now Collins could move them to their new home in the Mt. Baker-Snoqualmie National Forest, where they’d be reunited to begin work on another dam.

The project maintains trail cameras in relocation sites to ensure they don’t drop beavers off in another family’s territory, Collins said. An added bonus is that the team gets to watch the newly moved-in beavers get comfortable and start work on building a better habitat for themselves and their neighbors.

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But just because one beaver family is out of the picture doesn’t mean another can’t move in and take their place, Higgs said.

The naval station is now working with Beavers Northwest, a Western Washington-based conservation group, to make sure future dams don’t wreak the same havoc. They’ll install devices, aptly known as “beaver deceivers,” to allow water to flow through a dam without its builders ever noticing the difference.

Collins said the Tulalip Beaver Project encourages anyone dealing with pesky beaver neighbors to reach out to the project. The team doesn’t charge for their services, and chances are the dispute can be resolved to everyone’s liking.

Riley Haun: 425-339-3192; riley.haun@heraldnet.com; Twitter: @RHaunID.