Can beavers help heal burn scars after wildfires? Colorado researchers built their own dams to find out

Elise Schmelzer, The Denver Post on Dec 30, 2025

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DENVER — High in the mountains west of Fort Collins, teams of scientists and engineers are pretending to be beavers.

They may not be swimming or chewing trees, but researchers with the U.S. Forest Service and Colorado State University are building fake beaver dams in burn scars to study how wetlands created by the dams impact ecosystem restoration and water quality after wildfires.

The research led by Tim Fegel is some of the first of its kind, he said. Scientists have studied how meadow and wetland restoration affects wildlife habitat, but there’s been little exploration of how wetlands created by beaver dams could change water quality post-wildfire, said Fegel, a biogeochemistry lab manager with the Forest Service who is leading the project.

“It’s kind of a brave new world for us with this type of work,” said Fegel, who is also a doctoral candidate at Colorado State University.

Wildfires destabilize soils and make them less capable of absorbing rain and snowmelt, resulting in higher runoffs and increased flood probability. High volumes of water, combined with a lack of vegetation roots to hold soil in place, mean that more sediment and debris travel downstream, impacting water quality and water treatment systems.

Five years ago, the Cameron Peak and East Troublesome wildfires ripped through Colorado’s northern mountains, charring more than 620 square miles across watersheds that provide water for hundreds of thousands of people who live along the Front Range.

That’s where Fegel and other researchers think the fake beaver dams can help.

Fegel hopes the work will provide land managers and water utilities with more data and, potentially, another water-quality tool.

The team installed beaver-style dams across the Cache la Poudre and Willow Creek watersheds — both burned in the 2020 wildfires — to help slow water flow and instead spread the water over a floodplain. Engineers designed the dams, which are generally made of large logs hammered into the earth with branches and other material.

The installations vary in size and complexity. Some are relatively simple, spanning a narrow stream and created by a team with a chainsaw and a sledgehammer. Others required heavy machinery and consist of dams across more than a mile of the south fork of the Cache la Poudre.

“It’s going to be really interesting to see, can you do this by just cutting a tree down and letting it flop in the stream and costing you 20 minutes of time?” Fegel said. “Or does it work better when it’s further down in the watershed from a bigger collection area, with these big, massive features?”

When obstructions slow down water, sediment in the water drops to the bottom of the channel instead of continuing downstream. Fegel is also researching how slowed water that spreads across a floodplain might keep more carbon and nitrogen higher up in the water supply, instead of pushing it downstream, where it can disrupt aquatic ecosystems or create algal blooms.

Some of the areas where Fegel is working used to be home to beavers. In one spot in the Cache la Poudre watershed, researchers believe a beaver has moved back into the area after they constructed the dam.

“The wetlands they create are promoting habitat for willows to grow, and those willows feed the beavers,” said Chuck Rhoades, a research biogeochemist with the Forest Service overseeing the project. “If you kickstart it by making these dams, then it may become better beaver habitat.”

But wild beavers are not beholden to engineers’ plans. They may build new structures elsewhere in the area. Researchers hope some of Colorado’s more than 60,000 beavers will continue to move back into the floodplains they create and plan to monitor where beavers decide to build their dams as part of the long-term research project.

“That’s really the long-term goal — to have the natural system restore these processes, instead of having these wooden posts in the ground,” Rhoades said.

While early results indicate that the beaver dams improve water quality, the team is now also assessing whether their use is practical at scale, Rhoades said. Work on the ground after a fire needs to happen quickly — within the first few years — and designing and constructing dams can take time and be expensive.

“We may be having some positive effects, but we may not be changing the post-fire landscape that much, or have a big enough improvement in water quality to make it worthwhile,” Rhoades said.

The research will likely continue for years as the team monitors the change that occurs, Fegel and Rhoades said.

“As part of the valuable supply network for Denver and Front Range water utilities,” Rhoades said, “keeping an eye on these watersheds is going to be a long-term commitment.”