With beavers missing from the landscape, humans do the dirty work

Scientists know beavers create landscapes better adapted to climate change. Here’s what they’re doing in ecosystems too degraded to support the critters.

Scofield • As Jordan Nielson tromped through recovering pastureland around Mud Creek, his boots occasionally got sucked into the soil, still saturated in the waning days of summer. It’s exactly what he wanted to see.

The creek had become so degraded by a century of cattle grazing it made several deep cuts in the bank, sloughing off the land and dumping sediment into Scofield Reservoir. All those nutrient loads spurred algal blooms, making the reservoir dangerous for swimming, fishing and boating. Now, the creek has slowed. Water diffuses into nascent wetlands that clean it and build habitat for wildlife.

It’s quite the transformation, and it only took a year to take shape using a simple technique — artificial beaver dams.

“It’ll be awesome for birds, for food production, for the fish, for trapping sediment,” said Nielson, Trout Unlimited Utah’s water and habitat program director. “It’s good at filtering runoff as it comes off of the fields and into the stream.”

The wetlands also turn the creek’s surrounding banks into a sponge, recharging groundwater so it slowly releases downstream throughout the season, flowing from Schofield to the Price River and, eventually, the Colorado River.

“We get water storage underneath our feet right here,” Nielson said. “We fill the water table, and then our water resources last us for longer, keeping cold, clean water for a longer period of time. That’s been identified as one of the top strategies for building resilience in the Colorado River Basin.”

(Francisco Kjolseth | The Salt Lake Tribune) An artificial beaver dam controls erosion and restores fish habitat along Mud Creek by Scofield Reservoir as Trout Unlimited gives a tour of one of its projects, Aug. 16, 2023.

Trout Unlimited built 75 artificial beaver dams — technically called “beaver dam analogs” or BDAs — at Mud Creek and nearby Winter Quarters Creek last fall. The method involves driving fence posts into the ground, then weaving sticks and reeds around them, effectively mimicking what a beaver would do.

So, why not just trap and release actual beaver, as scientists are doing to restore ecosystems across Utah, so the rodents can do the work at Mud Creek themselves?

“We’re hoping that it’s like an ‘if you build it, they will come’ kind of thing,” Nielson said.

Mud Creek has been heavily grazed for generations, so there are no trees or willows — the things beavers like to eat and use to build their homes. The idea is the BDAs will create the meadows and wetlands growing those kinds of things, and a fence around the creek means cows can’t munch them back down again.

“We think we know how to build beaver dams,” Nielson said, “but beavers actually know how to build beaver dams. So we just try and jump-start it.”

(Jordan Nielson | Trout Unlimited) Eroded banks causing sediment loads and harmful algal blooms in Schofield Reservoir are seen on Mud Creek in June 2020.

(Francisco Kjolseth | The Salt Lake Tribune) Artificial beaver dams and river bank shaping by Trout Unlimited along Mud Creek, with fencing to keep the cattle out, significantly improve fish habitat before it flows into Scofield Reservoir on on Aug. 16, 2023.

Trout Unlimited used a $400,000 EPA grant for the project, along with funds from Utah’s Watershed Restoration Initiative. They also used machinery to reshape banks, planted 4,000 willow shoots and spread 400 pounds of native seed. Nielson said it penciled out to cost about $600 per BDA.

“But that’s because I hired crews to come in and build them for me,” he said. “We’ve done smaller projects where we bring volunteers to help us build and they’re much, much less. You’re talking a couple hundred bucks a structure.”

And assuming the beavers do move in, it means no ongoing maintenance costs.

Utah State University professor and fluvial geomorphologist Joe Wheaton helped develop the method and coined the term “beaver dam analog” in 2009 while working on a project to restore steelhead trout and salmon habitat in Oregon.

“There was a group of us and probably too many beers,” he joked. “I regret the stupid acronym stuck.”

(Francisco Kjolseth | The Salt Lake Tribune) Jordan Nielson with Trout Unlimited gives a tour of their project along Mud Creek that flows into Scofield Reservoir where 75 BDAs (human-made beaver dams) were installed with a partnership with the EPA and Utah Division of Water Quality, Aug. 16, 2023.

BDAs have caught on in recent years. Trout Unlimited plans to build 2,000 in Utah alone by 2025, including in the Great Salt Lake watershed, using the surge in federal funds from last year’s Bipartisan Infrastructure Law.

Wheaton counts around 12,000 BDAs built in 15 states so far.

“We know that’s a dramatic underestimate,” he said. “Any time you have a nature-based solution that’s common sense, it’s exciting.”

Wheaton cautioned BDAs are not a magic solution to water shortages, however, especially in the Colorado River Basin.

“It’s not going to solve what we’re losing with diminishing snowpack,” he said, “and the changes we’ve been unwilling to make to our consumption.”

But a big part of the appeal of both artificial and natural beaver dams is how they build an environment that’s more adaptive to disasters fueled by climate change. They mitigate flooding. They inhibit invasive species. They protect water infrastructure and reservoirs from heavy sediment loads. They act as fuel breaks during wildfires, Wheaton said, and they release water throughout the year similar to snowpack.

At Mud Creek the landscape is already healing, even though the beavers haven’t taken up occupancy yet. Native grasses have taken hold, willows have resprouted and the banks dump less dirt downriver.

“The goal is not to build structures that last, the goal is to quickly promote natural structures and get them to the point they don’t need us,” Wheaton said. ”It’s offering a meal to the stream.”