How man-made beaver dam replicas can improve waterway health

About five years ago, Willie Stockman’s home on the banks of Emigration Creek became a hot spot for wildlife.

In the summers of 2017 and 2018, moose, coyotes and turkeys started showing up in her yard, where she had never seen them before. Huge herds of moose descended from the canyon and began to occupy her and the neighbors’ yards.

Although these creatures were a sight to behold, they were a sign of a bigger problem in the canyon: a severe drought had left the upper canyon with no water, so the wild animals were descending further down the canyon in search of a drink.

“Parts of Emigration Canyon are dry and have never been dry before,” Stockman said. “People were carrying large water tanks because there was no water. … And all this is part of the big problem.”

In 2019, Stockman, along with other Emigration Canyon residents, formed the Emigration Canyon Sustainability Alliance to improve water quality, increase river flows and protect wildlife through groundwater studies, septic system planning and other activities.

One method the group is exploring to help improve the health of the Emigration Creek watershed involves mimicking another wild creature, the North American beaver.

For many ecosystems, beavers are a keystone species, meaning that other animals and plants in the ecosystem could not survive without them. The industrious rodents’ dams create important wetland habitat for other species and help raise the water table so that plant roots receive a constant supply of water.

According to the Utah Division of Forestry, Fire and State Lands, beavers have been reintroduced over the decades to restore riparian areas adjacent to waterways, improve river health and create wetland habitat for birds and insects. But some of these areas are too degraded or damaged, with steep, eroded stream banks and a lack of vegetation to support beavers.

Keith Hambrecht, invasive species coordinator for the Utah Division of Forestry, Fire and Public Lands, shows a stake being used to build a beaver dam replica at Corner Canyon Creek in Draper on Monday, Aug. 8, 2022. Hambrecht said the structures were built to raise the water table and create a more favorable habitat for native riparian and wetland vegetation.

Christine Murphy, Deseret News

Beaver dam analogs, essentially human-made replicas of natural beaver dams, provide ecosystem and waterway benefits that will add toothed holes to areas that beavers can no longer inhabit. People set up wooden posts in the creek beds and then weave willows to fill the gaps.

The completed counterparts are intended to trigger natural processes of floodplain preservation, wetland restoration, native vegetation support, downstream sediment reduction, water quality improvement, and erosion reduction. Analogues can also improve streams enough to make them habitable for real beavers again.

One study in Oregon found that the analogues increased groundwater levels near streams where they were installed, and that they helped restore riparian areas by stimulating willow growth.

A study conducted in California found that analogs make it difficult to flow that was previously lost. The study also found that the analogs helped connect streams to other waterways through floodplains.

Another study in Oregon, commissioned by the US Forest Service, found that the analogues improved habitat for fish and other wildlife and that they could ensure the return of native beaver populations on farmland.

merlin_2934611.jpg

Rose Smith, Sageland Community Stream Ecologist, talks about a beaver dam analog at Corner Canyon Creek in Draper on Monday, Aug. 8, 2022. The structures were built to raise the water table and create a more favorable habitat for local riparian and aquatic swamp vegetation. .

Christine Murphy, Deseret News

Dozens of similar beaver dams have been installed on Utah rivers, including the Rose Creek catchment near Herriman and Tall Canyon near Summit Park, according to Sageland Collaborative stream ecologist Rose Smith.

Sandwiched between a golf course and a slew of new corporate buildings and apartment complexes is Galena Sunkahni Preserve, a 250-acre swath of wild sagebrush nestled in the suburbs. The Corner Canyon Creek section flows through the Draper Preserve, which is permanently protected by a conservation easement. It was here that conservationists began to install eight analogues of the beaver dam near the confluence of the stream with the Jordan River.

The small stream is so deep in the ground that you may not notice it until you fall into it. Invasive phragmites have taken over the creek banks with thickets so tall and thick that Kate Humbrecht, coordinator of the Utah Division of Forestry, Fire and Public Lands, used a chainsaw to clear them.

Still, Hambrecht and Smith say this stretch of creek is a great place for beaver dam counterparts. Land managers are trying to create as much habitat as possible for native species on the 250-acre preserve, and analogs are one way to do that, Hambrecht said.

“We know this land is protected forever, so it’s worth investing in,” he said.

On a hot August day, semi-finished counterparts of Corner Canyon are already starting to work as intended. Even though they are just poles sticking out of the water, vegetation gets in between the poles, helping to filter sediment out of the stream. In the fall, volunteers will finish installing the counterparts correctly, weaving willow and pine to insert between the posts.

Blue tubes installed around creek bed willows protect the plants from herbicides sprayed to kill phragmites and help their roots grow deep enough to find water that the invasive species hasn’t already siphoned off.

merlin_2934619.jpg

A willow seedling pops out of a pipe used to help it grow, protecting it from damage by animals and sprays used to kill invasive species, still exposed to sunlight on the banks of Corner Canyon Creek in Draper on Monday, Aug. 8 , the year 2022.

Christine Murphy, Deseret News

Smith hopes the analogs will expand the area on both sides of the creek where these willows and other native plants can find groundwater. The analogues would periodically cause water to flow over the creek’s banks and spread out, replenishing groundwater and expanding the riparian zone next to the creek where plants can grow, she said. If beavers are reintroduced to the area in the future, they will need a steady supply of willow for food, Smith added.

“Beavers are our friends, and there are many situations where we can live with beavers,” Smith said. “The more we can all find ways to do that, I think the better off we’ll be and the more resilient our riverscapes will be to drought and fire.”

When the analogs are finished, conservationists will evaluate how well they are doing with the system, which evaluates the analogs on 25 different indicators of stream and watershed health, including fish and wildlife habitat, riparian vegetation and water quality, she said. Environmentalists will also be on the lookout for similar drones.

Can beaver dam analogs raise water levels in the Great Salt Lake? Maybe not, says hydrologist Konrad Hafen, who studied the ability of beaver dams to store water as a researcher at Utah State University. According to him, the benefits of beaver dams and similar are likely to be more noticeable upstream in watersheds.

Hafen studied beaver dams in the Bear River basin, one part of the Great Salt Lake watershed. His research found that if all the water stored behind beaver dams in the Bear River Basin were released within 30 days—the best-case scenario—it would likely result in less than a 1% increase in flow. He added that it was not significant enough to measure it by most standards.

But beaver dams and their counterparts provide many benefits to streams and watersheds beyond water retention, and according to Hafen’s study, beaver dams’ ability to store snowmelt water is not insignificant. In areas where man-made reservoirs are not possible, beaver dams can act as dozens of tiny water storage tanks, Hafen’s research found.

“The places where it can increase is going to be higher up in the system, you know, on smaller streams that can support a high density of beaver dams,” Hafen said. “So those are the areas where you could potentially see an increase in stream (flow).”

While beaver dam counterparts have many benefits for stream health, they don’t work everywhere and are usually only intended as a temporary solution, Smith said. In cases like Corner Canyon, phragmites and other invasive species need to be cleared first, or beaver dam analogs can actually help the weeds continue to grow.

“If you’re not careful, you can create more habitat for invasive species,” Smith said.

Analogs also require regular monitoring, so you can’t just “set it and forget it,” she added.

merlin_2934605.jpg

Kate Hambrecht, invasive species coordinator for the Utah Division of Forestry, Fire and Public Lands, holds a houseplant that competes with invasive phragmites along the banks of Corner Canyon Creek in Draper, Monday, Aug. 8, 2022.

Christine Murphy, Deseret News

According to Hafen, the loss of beaver dams in areas where they were historically present is related to some of the same problems of suburban sprawl and agricultural expansion that are affecting the Great Salt Lake’s declining water levels. Urban areas on the Wasatch Front probably had more beaver dams before they were created for human habitation. And agriculture often uses land that might otherwise be suitable for beaver habitat, he added.

“I think there are many situations where putting in (analogs) or encouraging beavers to build dams can be beneficial, from an environmental or ideological standpoint,” Hafen said. “But I think you also have to look at it on a case-by-case basis, look at what the goals are for the restoration, what the restoration needs are, and how those things will affect the surrounding landscape.”

While the beaver dam counterparts may not directly raise water levels in the Great Salt Lake, Stockman believes they could be part of the process of improving the health of the lake’s watershed — and helping those elk, coyotes and turkeys avoid her backyard to be greener pastures up-canyon.

“Sometimes I think of Utah as … a dry orange. It’s not that there is no water – you can put a straw in, suck it out, and collect water in the tank. But to get the best fruit, you need to take care of the tree, and the tree is the watershed. That’s where our water comes from,” Stockman said. “Sometimes I think there’s too much focus on seeing the water and not realizing that’s all there is. We need to pay attention to the actual state of the watershed. And so (beaver dam analogs) is one way to do that.”

Leave a Comment

Your email address will not be published.