When flash floods filled Colorado Springs streets last summer, the water raged down from Black Forest all the way to Dallas May’s ranch north of Lamar.

The flood made the lengthy journey in just two days, but when it hit May’s wetlands, the water slowed way down. It took 2½ days to travel just 7 miles through the ranch, May said.

The muddy floodwaters left his property clean and clear, filtered by a wetland system created by beavers, who build their dams on the High Plains with bulrush and cattails, unlike their fellows in the mountains.

In the complex of wetlands, the water spread out across the flood plain and recharged the alluvial groundwater.

“It slowly returned to the river over months instead of hours,” May said.

The healthy wetlands keep water flowing in the creek through May’s ranch year-round and recharge the shallow groundwater keeping the grass healthy for his cattle. The wetlands also support a vast number of birds, small fish and native grasses. A team from the Denver Botanical Gardens documented 85 different species of grass, May said.

The longtime rancher lays the flood control, consistent water supply and other benefits at the webbed feet of the beavers.

“If it wasn’t for these beavers, there would be no water going into the (Arkansas) river from here,” May said. At twilight one day in October, May showed off several beaver ponds on his property during what is typically a dry time for waterways across Colorado. The beavers stayed well out of sight, but he described them as bigger than those in the mountains, and adventurous when necessary, venturing out of the safety of the waterways to trek across his alfalfa fields.

May also explained his philosophy for managing the ranch he’s worked since the 1980s and now owns with his family.

“Our goal is to keep everything in as natural a state as we can. … We don’t kill coyotes. We don’t kill prairie dogs. We don’t kill rattlesnakes. We don’t trap or poison anything. If God intended for a species to be here, we want it to be here,” he said. When the system is intact, it functions well. The coyotes have plenty to eat and don’t touch his cattle, he said.

The previous owners felt the same and so May’s ranch is home to a long-established population of beavers, he said.

Beaver’s parachute in Idaho

Across North America, before commercial fur trapping, an estimated 60 million-400 million beavers populated rivers and streams, said Ellen Wohl, a Colorado State University professor of geosciences, who has studied beavers’ role in river ecosystems.

At that time, river corridors wandered the landscape with many branching channels and obstructions like beaver dams, she explained.

“Over the last couple 100 years, we have worked very hard to make (rivers) more like drainage canals, and that’s efficient at conveying water downstream, but it conveys everything else downstream too,” she said.

After an extreme wildfire in Colorado, that can mean intense flash flooding carrying mud and debris into communities and homes.

Beavers can create wetlands that absorb those floodwaters as they did on May’s ranch, a benefit that’s not at all new.

But the interest in the benefits of beavers on the landscape has been cyclical, Wohl discovered while working on her book, “Saving the Dammed,” about a beaver meadow in Rocky Mountain National Park. Literature dating back to the 1930s showed the Soil Conservation Service saw potential in promoting beavers as a way to limit erosion. Around 1950, Idaho Fish and Game relocated beavers by plane, putting them in crates and sending them parachuting to the ground as part of an effort to preserve trapping opportunities. Restored video from the department shows a beaver scurrying off after landing, leaving the box attached to a parachute.

Now beavers are gaining attention again across the U.S., Western Europe, Australia and New Zealand as part of a strategy to promote resilience along rivers, Wohl said.

“They’re the charismatic face of trying to make river networks more resilient to extremes,” she said.

Restoring wetlands near Keystone

On the White River National Forest, along a dirt road beyond the Keystone Ranch Golf Course, Soda Creek looked like an irrigation ditch flowing through a field, narrow enough to step over.

Crews aimed to transform the field into a wetland by putting in 153 dams meant to replicate those beavers would build. In hard hats and waders, the crews drove posts across the channel and then placed rock and sediment around the base. Then they wove in willows and mud.

The National Forest Foundation helped raise money for the $1.2 million project that includes five years of monitoring and maintenance.

The dams are intended to start a transformation that will draw down beavers living upstream, who will maintain the area long-term, said Tyler Bell, director of Westervelt Ecological Services, Rocky Mountain Region.

“Beavers hear that sound of this running water, and they’re like, ‘Not today, we got to go patch that up,’” said Nick Picha, a conservation planner with Westervelt. “So hopefully they start to move in and start to build on what we’ve already started here.”

The small dams hold back the water, recharging the groundwater and allowing native wetland grasses to move back in. Over time, the valley will green up with a higher water table and new willows the crews expected to put in during November, Bell said. The willows will provide a food source for beavers and a natural cover from predators.

The new wetlands will also draw in new bird species, moose and others, Tyler said.

While the meadow was buried in snow this December, the dams had already started slowing down and spreading out water, and beavers were spotted in the area, said David Boyd, a spokesman for the National Forest.

Beavers on Pikes Peak 

As part of a similar project, Colorado Springs Utilities is hoping to draw in beavers to a 1½-mile stretch of North Catamount Creek above one of its reservoirs on Pikes Peak with 40 to 60 structures that will replicate beaver dams and restore a riparian area.

Annie Berlemann, the Fountain Creek watershed planning manager, expects a restored wetland will help settle out sediment before it reaches the reservoir and help keep the water cleaner.

Crews are expected to start work during September 2025, when the stream is running low, and they will use trunks and limbs from nearby forest thinning

She hopes beavers will be attracted to the area, particularly since there are old beaver dams in the area slated to get patched up as part of the project. Forest thinning will also make space for aspens, a tree species beavers love to munch on.

Utilities recently received a $1.37 million grant to fund the work. A large portion of that money, about $600,000, is helping to fund the forest thinning in the area. Utilities also expects to use the funding to monitor and adjust the project through 2026, she said.

The entire project will also help ensure that if the area burned, it wouldn’t be a catastrophic blaze, like Waldo Canyon fire. An open, healthier forest sees small and low intensity fires that benefit the landscape, she said.

“We don’t want to completely eliminate fire from the landscape,” Berlemann said.

Managing beavers

On private land, beavers can become a nuisance, taking down beloved trees. But trapping them and moving them out of prime habitat can just create a cycle of removal.

“If you take beavers out of good habitat, it’s like putting out the vacancy sign for other beavers,” explained Peggy Darr, with Defenders of Wildlife, who has worked on beaver habitat restoration in New Mexico.

A better strategy can be putting in structures to manage the beavers, such as wrapping trees with heavy-gauge wire and staking it to the ground, she said. Beavers need some trees as a food source to make it through the winter, but landowners can preserve those with special value that provide shade or fruit.

When it comes to the risk of ponds flooding, Darr said, large pipes can be installed as a safety valve to keep water at a safe level, even if beavers continue to build up the dam.

If downsides can be minimized, Darr said, beavers can bring numerous benefits such as keeping water flowing in rivers and streams even in dry times.

“If we can maximize the beaver potential on all of our rivers, it will be an amazing free resource for humans, you know, to help us with the effects of climate change, drought, et cetera.” Darr said. “And all we have to do is learn to live with them, which is pretty easy to do.”

Defenders of Wildlife also encourages everyone to report beaver activity on a citizen-science app called iBeaver, created in 2021. If it’s widely adopted the tool could help track population trend, as eBird has helped track avian populations.

It also helps identify potential areas for beaver conservation work, Darr said.

Resilient populations

When a high-voltage electrical line sparked a fire on Dallas May’s ranch in 2022 and swept across 9,000 acres driven by high winds, he didn’t think the beavers would make it.

During the fast-moving blaze, he was focused on evacuating as many cattle as possible, but a few wouldn’t follow him. They retreated instead to the beaver ponds for safety and made it through on their own.

“It burnt the hair on their backs,” May said of the fire.

While the fire consumed the beaver dams and most of the trees on the May ranch, at least some beavers made it through, burrowed into the sides of the creek.

Three or four months after the fire, the ranch started to get some rain that refilled the creek, May said, allowing the beaver to start their regular activity.

He has full faith they will move back into some of the dry dams that are currently uninhabited on his land — just as they are moving back into their old haunts all over Colorado.