Joe Timmerman / Wisconsin Watch
Katie McCullough on her pond in Rio.
Katie McCullough paddles across a pond on her property with her dog, Ky, near Rio. McCullough installed a pond leveler on her property after discovering an active beaver lodge and dam.
Katie McCullough arrived in Wisconsin in 2021. Her COVID pandemic purchase of 36 acres near the village of Rio in the south-central part of the state was exactly what she was looking for. She had purchased the property, sight unseen.
“I don’t regret it at all,” McCullough, 56, says with a laugh.
She soon met the neighbors — 15 to 20 furry lodge dwellers.
McCullough realized she had a beaver problem that made several acres of her property inaccessible.
They live atop a small muddy island and constructed a dam roughly a decade ago. Cattails grow across its 20-foot breadth. The dam left a once-lovely creek bone dry.
Backed-up water enlarged the surrounding marsh and pond, where sandhill cranes, geese and ducks meander.
Rooted in sodden ground, tall oaks — some more than 100 years old — withered and toppled.
Friends, family and locals recommended trapping the rodents and blowing the dam sky-high with Tannerite.
The solution seemed dramatic and destructive.
“We’re all here for a purpose, right? To think that beavers are just born a nuisance,” McCullough says. “It’s tough, because some populations do have to be controlled if there aren’t natural predators. But I’m not good at being a natural predator.”
Surely, other options besides trapping or bystanding existed.
Damming behavior
Beavers once numbered between 60 million and 400 million across North America, but development and unregulated hunting nearly decimated them. Twentieth-century conservation efforts helped beavers recover somewhat — to a fraction of their historical population.
Conflicts with humans ensued as beavers returned to their former ranges: chewing trees, plugging culverts, flooding roads and farm fields.
Few studies quantify the costs of beaver damage, and the limited data are decades old. One pinned annual timber losses in Mississippi at $621 million, adjusted for inflation.
Traditional responses involve trapping and dam breaching, but generally, these interventions require regular enforcement because new beavers move in. And an expanding body of research showcasing beavers’ ecosystem and economic benefits is drawing attention to the drawbacks.
When beavers remain on the landscape, they create wetlands, which mitigate climate change impacts like drought, wildfires and flooding — problems increasingly seen in the Midwest. Other wildlife also depends on the habitat.
Advocates and ecological consultants are popularizing flow control devices. They limit beavers’ damming behavior and reduce impacts on human infrastructure.
Hand-constructed with flexible plastic pipes and wire fencing, several types exist: pond levelers, culvert fences and decoy dams. Some bear trademarks like Beaver Deceiver and Castor Master.
They aim to reduce the desirability of potential dam sites, redirect beavers’ attention or “sneak” pond water away unnoticed.
McCullough opted for coexistence.
Wildlife agencies generally regulate a trapping season to manage beaver populations and minimize property damage. Wisconsin’s forestry and fisheries divisions, dozens of municipalities, railroad companies, and some tribal governments also contract with the U.S. Department of Agriculture to remove beavers and dams from designated lands and waters.
The state imposes few restrictions for handling nuisance beavers on private property. People may hunt or trap beavers and remove their dams on their property without obtaining a license. If a beaver dam causes damage to a neighboring property, the injured party may legally enter the property where the dam lies and remove it.
There also are risks to ignoring one’s beavers. People who own or lease beaver-occupied land and don’t allow their neighbors to remove them are liable for damages.
Ditching dynamite
But Wisconsin wildlife managers recommend people consider alternatives before killing the animals, including flow devices like pond levelers.
They date to at least the 1920s when USDA Chief Field Naturalist Vernon Bailey proposed using an “entirely successful” drainage pipe constructed with logs and threaded through the dam.
Subsequent testing indicated that early levelers sometimes failed, but the concept has evolved.
Courtesy of Clay Frazer
Dan Fuhs with a pond leveler.
Dan Fuhs, co-owner of Native Range Ecological, installs a pond leveler.
Modern devices control water height using a flexible plastic tube resting on a pond’s bottom. A cage surrounds the intake and prevents beavers from swimming close enough to detect flowing water, which researchers believe triggers their building itch. The other end of the tube passes through the dam, forming a permanent leak.
Installers say levelers, which cost $2,000 to $4,000, function for about 10 years, and require little maintenance. They can modify setups to accommodate fish passage, narrow and shallow streams, large ponds and downstream beaver dams.
“The best solutions, obviously are going to be ones that work for the beavers and that work for us,” says Massachusetts-based Beaver Solutions owner Mike Callahan, who has installed more than 2,000 flow devices and trains consultants.
States throughout the Mississippi River basin, including Illinois, Kentucky, Minnesota and Missouri, recommend flow devices, but with varying awareness of best practices.
Pond levelers relatively uncommon in Wisconsin
Wisconsin residents have constructed beaver pond levelers, as have the Department of Natural Resources and USDA. But state natural resources staff say they rarely receive inquiries.
Despite their simple design, obtaining state authorization to install a flow device often takes longer than other activities like small-scale dredging and riprap installation because Wisconsin lacks a standard pond leveler permit.
Projects can vary across designs, siting and placement, with potentially significant impacts to where and how pond water flows, says Crystal vonHoldt, department waterways policy coordinator for the Wisconsin Department of Natural Resources.
The law requires employees to evaluate impacts to water quality, navigation, wildlife, scenic beauty, and public access to boating and fishing.
A department staff member told McCullough’s contractor and restoration ecologist Clay Frazer — who has overseen multiple beaver-related projects in Wisconsin like mock beaver dams — that many landowners opt not to install them after learning of the challenges.
Hiring a consultant to navigate the process can be cost-prohibitive. McCullough’s bill exceeded $10,000, but a grant offset it.
Proponents say the requirements usher landowners toward a lethal resolution, which Wisconsin’s beaver trapping rules seemingly favor.
Community levels with beavers
Billerica, Massachusetts, had a flooding problem.
The town’s troubles followed a 1996 statewide voter referendum that banned foothold traps. Conflicts increased as the beavers expanded into the community, home to more than 42,000 residents along with wetlands, streams and two rivers. Prime habitat.
Things came to a head in 2000, and the town contracted with Callahan to address the problem non-lethally. At 43 locations where Billerica traditionally trapped, he installed flow devices.
“They’re kind of instrumental in preventing certain culverts and major roads here in town from getting flooded,” says Isabel Tourkantonis, the town’s director of environmental affairs.
Trapping continued at another 12 sites because the devices either failed or the landscape made their use untenable.
Non-lethal management saved Billerica taxpayers $7,740 annually in avoided trapping and dam-removal costs, according to a town analysis. The number of beavers killed dropped more than fivefold.
Maintaining 380 acres of beaver-created wetlands provided an estimated $2 million of free services each year, including water filtration, flood reduction and plant and wildlife habitat.
“If there’s a way to co-exist with an important animal population, that’s, I would think, the goal,” Tourkantonis says.
Massachusetts landowners navigate a different permitting process for flow devices.
They only need to obtain approval from a local health board or conservation commission — generally at little cost. It takes a few days.
Tourkantonis says such procedures cut “through the red tape and make it a little bit easier for folks to address an immediate public safety hazard.”
Flow devices have limits
Scientists have conducted virtually no peer-reviewed research evaluating the effectiveness of flow devices.
But studies supporting their use documented financial savings, high customer satisfaction and trapping reduction.
Callahan analyzed 482 sites where he added flow devices or trapped and found only 13% of pond levelers failed within two years compared to 72% of trapping sites to which beavers returned.
Yet flow devices aren’t silver bullets.
A study conducted by the USDA’s wildlife control agency in Mississippi indicated that half of levelers failed to meet landowners’ goals — although the participants didn’t always maintain them.
Callahan, like many coexistence proponents, attributes device ineffectiveness to the faulty installation of outdated models. They say this can confirm preexisting beliefs that flow devices are ineffective, or at best, temporary solutions.
“If you have a crappy design, yeah, it’s not going to work.”
But Callahan estimates one in four beaver showdowns in Massachusetts require trapping.
Levelers aren’t effective in high-flow streams or developed floodplains, he says, where even a foot of water could swamp a home or neighborhood.
Drainage and irrigation ditches also aren’t ideal sites, nor are locations where water must be lowered to a depth in which beavers can’t live. Jimmy Taylor, assistant director of the USDA’s National Wildlife Research Center, says flow devices have their uses but aren’t a beaver control substitute.
Damage control can alternatively involve removing dams, lodges and the plants beavers eat; installing fences or scary props and noisemakers; applying spicy or bitter repellants to food sources; and shooting.
People tolerate beavers until conflict reaches a threshold.
One survey found that most landowners were open to beavers remaining on their property when they were offered incentives — a finding that could bolster support for investing in non-lethal techniques.
Previous efforts in Congress to appropriate several million dollars toward those efforts have proven unsuccessful.
Seeking to change ‘hearts and minds’
Frazer and McCullough hope to streamline Wisconsin permitting, making their case “one good flow device at a time.”
“It’s statutes. It’s permitting,” Frazer says. “But it’s also just hearts and minds. It’s people changing the culture of how they think about beaver.”
Their ponds look messy — dead trees and all — but to beaver backers, their value rivals rainforests or coral reefs.
A smiling, buck-toothed beaver statue sits on the gravel driveway outside her home. Its concrete paws grasp a skinny tree stump, chewed to a sharp point.
McCullough’s sister, who lives in North Carolina, located the cartoonish creature on Facebook and gave it a fresh paint job — a family rib over McCullough’s beaver troubles.
Too heavy to mail, the 50-pound figurine hitched rides to weddings and socials, crawling its way north to Wisconsin like a baton handoff in a relay. After a year, it finally arrived.
After a year, it finally arrived.
Wisconsin Watch is a nonprofit, nonpartisan investigative newsroom
