Humans mimicking beavers to combat wildfires and restore wetlands

Researchers in Colorado have built hundreds of dam-like structures in hopes of mimicking a fraction of the success the state’s beavers have had throughout history. Ashley Hom with the U.S. Forest Service co-leads Colorado’s largest beaver-based restoration project — along with many partners. In just two years, this team built 316 beaver mimicry structures, about half of which were BDAs, or beaver dam analogues — manmade structures that imitate beaver dams. Many of them were constructed by volunteers, according to a story by Julie Cleveland.

These BDAs are built using wooden fenceposts and willows that act as a low-cost and low-maintenance structure to protect areas from wildfire while maintaining or improving water quality.

The loss of keystone beaver populations has caused a negative impact on watersheds throughout the western United States. Dams that beavers create slow the flow of spring run-off while raising the water table to keep the landscape wet. Without beavers and their dams, streambanks have eroded, causing snowmelt and run-off to drain too quickly from the landscape.

Beaver dam on Baugh Creek near Hailey, Idaho. USFWS photo
Beaver dam on Baugh Creek near Hailey, Idaho. USFWS photo

“As beavers create and maintain wetlands, the outcomes are vast,” Cleveland wrote. “A lack of beavers has resulted in an increased intensity of drought and wildfires in the West as fires spread rapidly across parched landscapes. Wetlands act as natural fuelbreaks, giving firefighters a chance for containment.”

The effectiveness of beavers against wildfires has been seen in real-time. The 2018 Sharp Flats Fire burned more than 60,000 acres in Idaho, but seemingly left one area untouched.

Loading beavers for transport
Idaho Fish and Game officers load a beaver into a wooden box before he’s loaded on a plane and dropped into the Idaho backcountry. IDFG photo

Nearly 70 years beforehand, Idaho Fish and Game had rounded up and relocated beavers, sometimes by parachute, throughout the state, including the Baugh Creek area.

Beavers in wooden boxes drop from a plane into the Frank Church Wilderness to start a new life.
Beavers in wooden boxes drop from a plane into the Frank Church Wilderness to start a new life. IDFG photo

The Sharp Flats Fire burned all of the land around Baugh Creek, but the beavers’ dams and the wetland they created were left unburned.

The contrast was so stark that researchers at Boise State University and Utah State University teamed up with NASA to start building tools to measure the benefits of beaver reintroduction in other areas of the country.

Post-burn image of the Sharps Flat burn, image by NASA.
Post-burn image of the Sharp Flats burn, image by NASA.

Watch the below video to see what researchers are paying attention to after beavers make their way back to wetlands — beaver rewilding as measured by NASA:

Alert reader Tom Jones sent over some photos he took of the beaver habitat on the B&B Fire in Oregon.

“We were with the NW Oregon type 2 team in September 2003,” wrote Tom. “Robert Alvarado was the Human Resource Specialist (HRSP) and I was the FBAN. Robert liked to go out on the line and talk with the crews to see how they were doing. I went to the line every day, so he would go with me. Each morning after briefing he would ask me, ‘What kind of adventure are we going to have today?’ The last two photos are of me and Robert at Marion Lake.”

Beavers' Fireline, B&B Complex 15. September 2003. Tom Jones photo.
Beavers’ fireline, B&B Complex 15. September 2003. Tom Jones photo.
Beaver Swamp Burned, B&B Complex, September 2003. Photo by Tom Jones.
Beaver swamp burned, B&B Complex, September 2003. Photo by Tom Jones.
Robert Alvarado and BeaverLine, 2003 photo by Tom Jones.
Robert Alvarado and BeaverLine, 2003 photo by Tom Jones.
Fireline put in by beavers on the B&B Complex in Oregon. 2003 photo by Tom Jones.
Fireline put in by beavers on the B&B Complex in Oregon. 2003 photo by Tom Jones.
Robert Alvarado at Marion Lake on the B&B Complex in Oregon. 2003 photo by Tom Jones.
Robert Alvarado at Marion Lake on the B&B Complex in Oregon. 2003 photo by Tom Jones.
FBAN Tom Jones with the NWOregon type 2 team in September 2003 on the B&B Complex. Photo by Robert Alvarado.
FBAN Tom Jones with the NW Oregon type 2 team in September 2003 on the B&B Complex. Photo by Robert Alvarado. (I didn’t know there were crocodiles in Marion Lake, did you?)

from Wikipedia:  The B&B Complex was a linked pair of wildfires that together burned 90,769 acres (367.33 km2) in  Oregon in the summer of 2003. The complex began as two separate fires, the Bear Butte Fire and the Booth Fire; the two fires were reported on the same day and eventually burned together, forming a single fire area that stretched along the crest of the Cascade Mountains between Mt. Jefferson and Mt. Washington. On the western side of the Cascades, the fire consumed mostly Douglas-fir and western hemlock. On the eastern side of the mountains, the fire burned mostly Ponderosa pine, lodgepole, and jack pine. Most of the burned area was on USFS land, including 40,419 acres (163.57 km2) within the Mt. Jefferson Wilderness. The fire also burned forest land on the Warm Springs Indian Reservation and small areas of state and private land. Firefighters worked on the fires for 34 days.

THANKS, Tom, for the great photos and another
piece of Beaver history in the Beaver State!
 ~ Kelly Andersson


The Oregon Supreme Court ruled in favor of beavers — in 1939

A lawsuit between two landowners

Beaver Dam
Beaver dam. Wyoming Game and Fish Department photo.

When Paul Stewart bought his rangeland in Eastern Oregon in 1884 it included a meadow with “stirrup-high native grasses”. The sub-irrigation provided by Crane Creek was amplified by several families of industrious beavers who had built numerous dams across the stream to form ponds for their homes.

In 1924 he left his farm for a year and upon returning found that poachers had trapped and removed the beavers. The dams had washed out and over the next 12 years the meadow and the creek was transformed. Uncontrolled flood waters eroded the banks, cutting into his valuable crop land. The stream was flowing 15 feet below its original level and the water table had dropped. The meadow was drying up and a well was barely producing any water.

Mr. Stewart arranged for the Oregon State Game Commission to bring him sixteen of nature’s hydraulic engineers — native beavers.

Below is an excerpt from a document written in 1941 by Paul W. Schaffer, the Regional Biologist for the U.S. Forest Service’s Pacific Northwest Region.

“The beavers began their reclamation work at once. They erected strong dams almost overnight; they sent huge cottonwoods and aspen crashing into the gully; they built more and more dams.

“When the heavy spring run-off came, water that for the past twelve years had rushed through the stream channel to be lost in the river below was caught behind the beaver dams and stored in large ponds which acted as settling basins for the silt-laden waters. At each flood stage of the stream, inches of soil were added to the bottom of the deepened channel. As the ponds were filled, excess water flowed over well-designed spillways and continued down the stream.”

The average summer streamflow of the preceding twelve years was increased considerably by the water escaping from storage. Water from the ponds percolated into the banks to the adjacent fields. Hay production in the meadows improved. The well again supplied ample stock water. The ugly erosion scar through the meadow was healing.

To make a long story shorter, Mr. Stewart’s downstream neighbor, Lloyd Johnson, urged Mr. Stewart to remove the beaver dams thinking it would improve the condition of his own eroded land. He did not realize that if the dams were blown up that the water would simply flow through his land, unimpeded by any structures, resulting in little if any change in his water table.

Mr. Johnson filed a lawsuit to have the beaver dams removed. He won. The judge ordered Mr. Stewart to within five days ask the State Game Commission to remove the beavers and the dams. He was also ordered to pay a $300 contempt fine and was threatened with three months in jail if he did not comply.

Mr. Stewart appealed to the Oregon Supreme Court which ruled in his favor, writing in part:

“To deny our water users the right to control such streams and prevent the erosion that would soon take place would mean the utter destruction of much of our most valuable lands throughout the state.”

Below is Mr. Schaffer’s nine-page beautifully written and typed description of Mr. Stewart’s experience with the beavers, crafted in 1941. It even includes an epilogue. Notice how both the right and left margins are justified, a long and tedious process when done on a typewriter. (You may also download the document.)

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It would be very interesting to know the present condition of Mr. Stewart’s former property, which he sold shortly after the 1939 court cases.

The Wyoming Game and Fish Department has a helpful guide to the beaver’s role in riparian habitat management.

In case you missed it, check out our May 5, 2021 article about how beavers can affect wildfires.

If you’re still starving for more information about beavers, Heidi Perryman, Co-Chair of last month’s California Beaver Summit, tells us that their website has information about presentations made at the conference, including the effects on wildfires, managing the challenges beavers can cause for landowners, and the value beaver engineering can have for the drying state of California. She said two of the researchers mentioned in our May 5 article, Dr. Emily Fairfax and Dr. Joe Wheaton, gave keynote talks at the conference. There were also speakers from the California Department of Fish and Wildlife, US Forest Service, and Bureau of Land Management.

Thanks and a tip of the hat go out to Kelly for letting us know about this case.

Beavers can affect wildfires

Their dams create wetlands affecting vegetation type, fuel moisture, and local humidity

American Beaver
American Beaver. Photo by Steve from Washington.

The job of a beaver is to build a dam and lodge across creeks using tree branches, vegetation, rocks, and mud. They chew down trees for building material. Dams impound water and lodges serve as shelters. Their infrastructure raises the water table and creates wetlands used by many other species, and because of their effect on other organisms in the ecosystem, they are considered a keystone species.

This storage of water can change the vegetation type as well as the moisture content in the live and dead fuel. Wetlands usually do not burn in a wildfire and they can serve a barrier to its spread.

However, beavers can also be a nuisance and can damage crops, timber, roads, ditches, gardens, and pastures by cutting trees, burrowing, or flooding areas.

Wetland created by beavers Sharps Fire
Wetland created by beavers in Baugh Creek in Idaho, part of the Sharps Fire.

The website is a not-for-profit publication, “Created by Californians seeking to protect California from wildfire. We can help one another to safety by welcoming back native beavers and traditional prescribed burning of brush.”

Photos from their website show the change in a creek after beavers moved in.

Beaver dams at Susie Creek
Beaver dams at Susie Creek, from

An article by Lucy Sherriff at the Sierra Club’s website explores how beavers can change the landscape, including their effects on wildland fires.

[Dr. Emily] Fairfax began to carry out the scientific research that she had hoped to find. Using satellite images, she mapped vegetation around beaver territories before, after, and during wildfires (footage of wildfires in progress can show how a fire moves through a landscape). She visited field sites in California, Colorado, Idaho, Oregon, and Wyoming and found sections of creek that did not have beavers were on average more than three times as affected by fire—burning a bigger area—than areas where beavers had built dams.

“I expected some of the time beaver dams would work,” says Fairfax. Instead, she found the presence of beavers had significant effects. “It didn’t matter if it was one pond or 55 ponds in a row. If there were beaver dams, the land was protected from fire. It was incredible.”

Fairfax hopes her research will help change California’s strict rules around beaver relocation, the way policy is already changing in Washington, especially as wildfires in California have reached record-breaking levels over the past several years.

Meanwhile, Fairfax’s research on beavers and wildfires is only beginning. “I set out to ask a question: Do beavers keep the land green during fires, yes or no?” she says. “The answer was yes. But that’s not the end of the story. Why? How? Does this happen everywhere? What if you have a tight canyon? I’m digging into the specifics now, so people can implement this and actually use beavers for fire prevention. I would love to be able to call someone up and tell them how many beaver dams they need in their creek.

“Right now I have so little advice on how to do it. But at least I can now say it works.”

The two-minute video below is a brief introduction to beavers. It appears to be an excerpt from an episode of “Nature”, titled, “Leave it to Beavers.”