This story by Briana Brady was first published in The Citizen on Feb. 27
For the last few years, a family of beavers has made a home in Geprags Community Park in Hinesburg, and they’ve been renovating.
A pond has sprung up behind their dam. Plant life has flourished. Fish have returned. And, according to Bob Hyams, a Hinesburg resident and owner of Riverscape Ecology, the surrounding wetland is now abating phosphorous at a rate higher than some human interventions.
The positive impact of the beavers at Geprags that Hyams has observed complements growing scientific knowledge about how beavers can help reconnect floodplains, abate phosphorous and ultimately revitalize the ecology of struggling wetlands.
During a presentation to Vermont legislators this month, Hyams put forth a proposition: the state should start paying landowners to manage beavers on their land.
Vermont has known about the excess phosphorous in the Lake Champlain watershed for years. As a necessary nutrient for plants, phosphorous is common in agricultural fertilizer. In an agricultural state like Vermont, that has meant phosphorous runoff from agricultural operations into the water system. However, although it helps plant growth, when in excess in waterways, phosphorous can cause water quality issues related to algae.
The state has been trying to address the phosphorous levels for years. Back in 2002, they established a plan to try to reduce the levels. However, when the Environmental Protection Agency (EPA) assessed Vermont’s plans in 2011, they mandated that the state take even greater measures, setting a timeline for the state to start in 2016.
“And the U.S. EPA says, Vermont, you got clean up Lake Champlain, right? They give you a bunch of money to do it, but we need to see results. So that was really the impetus for coming up with this functioning floodplain initiative,” Hyams said.
The functioning floodplain initiative aims to fund wetland and floodplain restoration. In measuring phosphorous abatement, Hyams said, the state uses floodplain reconnection as a proxy. That’s because floodplains and wetlands have been shown to act as phosphorous sinks, the plants that thrive in those environments absorb phosphorous from the water as it floods and settles into the ground.
When the beavers moved into Geprags a few years ago, Hyams saw an opportunity to observe the kind of impact beavers can have on phosphorous absorption as they interact with the landscape. According to Hyams, a lot of streams in Vermont suffer from incision, a process in which the streams straighten out and carve vertically down into the ground rather than curving through the landscape. This causes the velocity of the streams to increase, curbing the amount of water that gets absorbed into the ground. Beavers, in building their dams, fight that process.
In the presentation he gave to the legislature, Hyams pulled up a map of Geprags from 2018. The stream moves through a brown landscape in a fairly straight line. Hyams then overlaid an image that was taken with a drone after three years of beaver activity. A pond flows out over the plain, plant life spreads out from the waterway.
“There’s habitat for everything,” Hyams said. Using the same methodology the state uses to measure floodplain reconnection, Hyams assessed that the beavers had precipitated 25-30 kilograms of phosphorous absorption, more than has been measured at manmade phosphorous absorption projects in the county. Hyams has estimated, using the information Chittenden County Regional Planning Commission has about its own projects, that the beaver’s work was worth about $750,00. The beavers did it for free.
Beavers have other ecological benefits beyond phosphorous absorption. In reconnecting floodplains, they also help with flood management. It might seem counterintuitive that the minor flooding in wetlands helps prevent issues from major floods, but the ways in which wetlands provide winding streams slows water down, spreads it out, and helps it absorb into the ground.
Some of the projects in the state that seek to do floodplain reconnection use beavers as inspiration. Allaire Diamond with the Vermont Land Trust has looked at how beaver analogs — essentially, dams built by people — can help revitalize wetlands. She said finding space for actual beavers to do their work is something the state should explore.
“If we can just give them space to do their work and support them in whatever ways they need, then that feels like a really good use of our resources,” she said.
Diamond said there are plenty of places in the Vermont landscape where beavers could be managed without getting too close to human settlements.
For Hyams, it makes perfect sense to use some of the money the state has allocated for floodplain restoration to landowners managing beavers. The state already provides analogous funding for things like river corridor easements or carbon credits. And, right now, there isn’t much incentive for landowners to keep beavers on their land — after all, they’ve long been understood as nuisances.
“I think the majority of people that take out beaver dams think they’re doing it as a public service,” Hyams said. “I just want the state once, one time, to pay landowners for the phosphorus reduction values that beavers created.”
Should the Legislature take on Hyams’ idea, the cost of doing that might start to look pretty attractive, and maybe, just maybe, landowners will start sending out invitations to beavers.
Read the story on VTDigger here: Busy beavers play outsize role in cleaning up waterways in Hinesburg and Vermont.