Harnessing the Power of Beaver Dams to Combat Wildfire Impacts

Today, my office looks a little different than what you’re likely to picture. I’m waist-deep in a pool of slow-moving water above a small dam constructed of willows, woody debris, and mud. The sky is clear and deep blue overhead, but on the horizon, a thunderstorm builds above a forest of skeletal trees, burned in the 2024 Pack Trail Fire just east of Grand Teton National Park.

GYC’s Kurt Imhoff admires a beaver dam in Sheridan Creek. Photo GYC/London Bernier

I’ve been working alongside agency staff and a Conservation Corps crew to build a slew of imitation beaver dams in Sheridan Creek, a small tributary to the Wind River. This site immediately downstream of the burn is ideal for a post-fire habitat restoration project. We often think about the immediate impacts from—and responses to—fire in terms of displaced wildlife, or risks to our lives and property. We’re here, however, because of wildfire impacts to rivers and riparian areas.

The hills around us are blackened and burned. Small tributaries to Sheridan Creek—once slow and methodical in their route to join the larger stream—are steeper, straighter, and downcutting into the soil. Along the main river channel, we see sections of burned willows and large in-stream deposits of mud. This watershed could see peak flows double compared to the pre-fire condition. These are prime examples of how wildfires affect watershed function, and how tweaking those processes then manifests as changes to river form and function. To put it simply, rivers look and act differently following a wildfire.

The impacts of fire to rivers are significant and last for years to decades, until vegetation can recover and key physical processes begin to normalize. Wildfire, of course, is a natural and beneficial process in Greater Yellowstone. It’s nature’s reset button—our native plant and animal species are well adapted to periodic burn events and their impacts on habitat. The same is true with wildfire effects on our rivers and streams. As long as our rivers are functioning properly before the fire occurs, recovery can be expected with little to no intervention by people.

The rub, however, is that many streams that burn already experience some kind of habitat degradation. Whether it’s from overgrazing, extensive road networks, beaver removal, or logging, rivers that have been negatively impacted by human activity lack the ability to handle the impacts caused by wildfire. So, when a fire rolls through, the flooding of water and flushing of sediment worsens existing habitat challenges and reduces ecosystem health. And with larger, more frequent fires every decade, many streams are struggling to keep up. As a result, federal and state agencies are teaming up with partners like GYC to work on projects that help degraded streams recover faster from the increasing risks posed by wildfire.

The project site in Sheridan Creek below the Pack Trail Fire burn area. Photos GYC/London Bernier

Sheridan Creek is a prime example of a watershed that is vulnerable to wildfire. Already degraded, it was at a high risk for further habitat loss and degraded function after the Pack Trail Fire. GYC and its federal and state agency partners jumped in to help.

By building imitation beaver dams—known in the field as Beaver Dam Analogs, or BDAs—we can mimic the ecological benefits of natural beaver activity. These structures capture and slow post-fire sediment, holding it on-site instead of allowing it to wash downstream. This provides multiple benefits, from protecting spawning habitat for native cutthroat trout to improving connection between the river and its adjacent floodplain. It’s just one of many approaches that fall under the umbrella of “low-tech” restoration—intentionally simple projects that can be built by hand using natural materials and at low cost. This allows for a project to get underway quickly, and for a large area to be restored. Ironically, these intentionally simple techniques are one of the most cutting-edge approaches in stream restoration.

This project is just one low-tech effort that GYC is currently pursuing. Since 2023, GYC has been researching and testing different low-tech restoration techniques to promote post-fire recovery in degraded stream systems. Sheridan Creek is just the beginning.

The Greater Yellowstone Ecosystem is the headwaters of the West, and the health of our rivers affects local communities and those far downstream. GYC works to keep the region’s rivers wild, clean, and free flowing so wildlife and people can thrive. We will continue to work collaboratively to understand regional threats to water, prepare for a warmer, drier future, and protect waters and lands from increased wildfire pressure.

– Kurt Imhoff, Sr. Climate and Water Conservation Associate [Lander, WY]