“I’ve never done anything like this before,” said Gianna Karlen. Karlen is studying Environment, Sustainability & Geography and Earth and Environmental Sciences. “Getting into the water and the environment, and seeing firsthand how beaver ponds and dams work, is really interesting and fun.”
The students—there that morning with their GEOG 4806 Beaver, Moose, Wolf class—and their instructor, Afton Clarke-Sather, partnered with the City of Duluth to install a Beaver Flow Device. A system designed to allow beavers to remain in the area while keeping water levels low enough to protect the surrounding trails—home to some of Duluth’s most pristine hiking, biking, and walking.
The flow device system, implemented by Clarke-Sather and his students, was originally developed by groups on the East Coast in the 1990s.
“The system consists of a cage, and it’s based on the principles of deception and exclusion,” Clarke-Sather explained. “Beavers respond to two things: the sound of moving water and the feel of water flow. So, we exclude them from the pipe’s entrance and deceive them into thinking no water is flowing through it because they can’t get close.”
The students began that morning by preparing the dammed area for the device’s installation. Ben Karlgaard, a senior studying Environment, Sustainability & Geography at UMD, eagerly waded into the pond—sometimes up to his chest—to help with the work.
“Today, we’ve been cutting a notch in a beaver dam,” Karlgaard said. “We’re installing a flow device because upstream flooding is affecting the boardwalk, and if we just made a hole, the beavers would plug it back up.”
Beavers benefit ecosystems in many ways. Their dams create wetlands that improve water quality and prevent flooding, while providing crucial habitats for diverse species. By storing water, they reduce drought severity and even act as natural firebreaks by increasing moisture throughout the landscape. As a keystone species, beavers support many plants and animals by creating habitats that offer food and shelter.
“Beavers provide some of the greatest ecosystem benefits we can think of,” Clarke-Sather said. “And they do it cost-effectively. But from an environmental perspective, the challenge is that you lose control—you don’t get to choose where they go. They’re animals that make their own decisions. So, when we look at beaver mitigation, we’re trying to balance the benefits beavers bring to the environment and ecosystem with protecting the infrastructure we rely on.”
One passerby walking their dog expressed some skepticism about the project but mentioned they enjoyed walking the trail each morning to see what the beavers had done overnight. Clarke-Sather emphasized that the project’s goal is to allow beavers to live in the area without damaging the trail infrastructure that’s so important to the Duluth community.
“With beaver mitigation, we’re seeking a balance,” Clarke-Sather said. “This project offers an alternative to trapping. Beaver removal is often the first option people consider, but this system is designed to help us coexist with the beavers while protecting our trails.”
With innovative solutions like the Beaver Flow Device, UMD’s students and community are demonstrating how coexistence with nature can protect both the environment and the places people love to explore. In the end, it’s about working with the beavers, not against them, to keep the trails—and the wetlands—thriving for generations to come.