Busy as a Beaver

Restoration practitioners mimic beaver to revive Colorado streams

With many of Colorado’s riparian areas at risk, researchers and watershed managers are turning to nature’s master river engineer for help.

When David Cooper started a research project in Rocky Mountain National Park’s Kawuneeche Valley in northern Colorado in 1996, he chose to eat his lunch at the top of a sunny, 60-foot hill with an uninterrupted view of the Colorado River headwaters below.

Over the course of two decades, Cooper, a senior research scientist emeritus of wetland and riparian ecology at Colorado State University, returned to the hill with his camera to create a visual timeline of the ecological collapse occurring before his eyes.

Cooper’s research team found that the 86-year-old Grand Ditch––a 15-mile water diversion that siphons 20,000 acre-feet of water per year from the Colorado River and transports it to the arid Eastern Plains––had dried out the valley floor, making it difficult for riparian trees and shrubs to grow. Swelling elk and moose populations were overgrazing the remaining vegetation, leaving an already dwindling beaver population with few building materials for their dams. The area’s beaver population was critical to keeping the ecosystem healthy. Without beavers’ careful stewardship, their ponds drained, decreasing the amount of surface water in the area by 95% and dramatically altering the hydrology of the valley, according to Cooper.

It’s a reality that plays out across Colorado and the West. Riparian areas––the lands along the edges of rivers and streams––and wetlands, have been degrading for decades due to mining pollution; overgrazing; flow alterations from dams, diversions and roads; and historical and present-day farming and timber management practices. Approximately 61% of smaller streams and 97% of major rivers in Colorado have experienced floodplain alterations, rendering them partially or wholly nonfunctional, according to a 2017 analysis for the Center for American Progress.

Cooper’s decades-long research helped inform the creation of the Kawuneeche Valley Ecosystem Restoration Collaborative, which is working to restore four riparian areas within the valley by protecting vegetation and mimicking beaver activity in hopes of luring nature’s master river engineers back to their historical homes. The project, which is primarily using low-tech, process-based restoration (LTPBR) methods, is one of dozens of LTPBR projects occurring across the state––bolstered by a recent influx of state and federal funding.

Process-based restoration (PBR) targets the root causes of ecosystem change, with restoration work tailored to restore a river’s natural processes. Those processes can occur watershed-wide or on a single reach and can include streamflow, flood storage, sediment transport and storage, biological processes, and more. LTPBR is a subset of PBR. While every site is different, LTPBR is generally lower in cost compared to other restoration approaches, and focuses on smaller streams using temporary and often natural structures—such as hand-built wood structures and sod plugs—to slow the water’s flow and allow it to spill out of the narrowed channel and reconnect to its original floodplain.

Beavers are taking over a beaver mimicry structure that was installed near Gunnison, Colorado. Photo by Jackie Corday

Research shows that connected floodplains and healthy riparian areas provide ample ecosystem services such as capturing sediment as it heads downstream; filtering out pollutants; storing more water on the landscape to increase vegetative growth and biodiversity; and moderating soil moisture, streamflows and temperatures throughout the year. All of this combines to make the watershed more resilient to floods, wildfire and drought.

But research surrounding LTPBR is fairly limited, especially as it relates to how projects might impact downstream water availability and the timing of flows.

Because of this, in part, the process for getting restoration projects approved in Colorado has been somewhat opaque and challenging for practitioners to navigate, prompting state lawmakers to draft a bill this session that sought to clarify the process in order to scale up efforts across the state. But the final bill was watered down through various amendments brought by industry groups who were concerned with how the projects might impact their priority water rights.

Still, scientists and restoration experts are pushing forward with projects, given the scope of riparian degradation and the strain climate change and population growth continues to have on water resources and the ecosystems that support them.

“We had the century of exploitation where we acted as if our natural resources were unlimited,” says Buffy Lenth, a watershed restoration specialist with Central Colorado Conservancy, an environmental nonprofit based in Salida. “Then, we had this century of preservation where we were like, ‘Oh my gosh, this isn’t limitless.’”

“The next century really has to be the century of restoration, where we take better care of the lands.”

Racing to turn “back the clock”

Jackie Corday, a land and water conservation attorney based in Montrose, became an enthusiastic proponent of LTPBR methods in 2018, after touring a private ranch in South Park, Colorado, where river restoration scientists successfully restored reaches of a stream that feeds into the South Platte River. The result was more water on the landscape, recovering vegetation, and a river that had repopulated with trout.

“I could see the difference. It just made sense,” Corday says.

At the time, Corday was the water resource manager for Colorado Parks and Wildlife and was asked by Brian Sullivan, the agency’s wetlands program coordinator, to research the benefits––and potential legal barriers––for scaling up those types of restoration projects.

Through her research, which culminated in the 2022 report for American Rivers, “Restoring Western Headwater Streams with Low-Tech Process-Based Methods: A Review of the Science and Case Study Results, Challenges, and Opportunities,” Corday found dozens of promising LTPBR projects in California and across the western U.S. that successfully “turned back the clock” on the damage done to various riparian areas, streams and wetlands in a more cost effective way.

“You can do it the fast way and come in with a big excavator and try to reset the elevation to what it would have been,” Corday says. “But that’s very expensive. It’s like $600,000 to $1 million a mile, and there are thousands of miles. It’s not even a possible approach [on its own].”

“Also, the science was showing that [a high-tech approach] wasn’t necessarily always bringing back the [ecosystem] that you were hoping for,” she adds.

“What these researchers were showing was that, well, there’s actually a better way to do this. You mimic beaver.”

Beaver dams have been shown to retain sediment and nutrients, as well as heavy metals, which can improve water quality. A study of 13 beaver ponds in England found that over a four-year period, the ponds trapped a total of 101.5 tons of sediment. And a 2020 study of large western U.S. wildfires published in the Ecological Society of America Journal Ecological Applications found that riparian vegetation around beaver complexes had a three times greater rate of survival than around stream segments without beavers.

Researchers and restoration practitioners in Colorado are building beaver dam analogs and focusing on other LTPBR techniques using natural materials—this is often cheaper and faster to implement than high-tech approaches, at just $50,000 to $100,000 per mile. An example of an LTPBR method would be to install posts vertically into a creek bed to catch wood and debris floating downstream, mimicking natural log jams. This can jumpstart a beaver’s home, which naturally slows the flow of water to allow it to pool and rehydrate the soil.

While LTPBR is seemingly growing in popularity, it’s not always the right tool. Sometimes, higher-tech engineering is needed, such as after major flooding events, below dams that alter flows, or when a river’s natural processes have been strained to the breaking point, rendering them unable to self heal, according to a design manual created by Joe Wheaton, an assistant professor of fluvial geomorphology at Utah State University.

The Beaver Restoration Assessment Tool was designed by Wheaton and his colleagues to help land and water managers identify the historical capacity of streams to support beavers and locate where they might feasibly be able to return. Since 2021, the Colorado Natural Heritage Program at Colorado State University has hosted a state-adapted version of the beaver assessment tool for the perennial stream network in Colorado.

LTPBR also may not be appropriate near housing developments or busy roads, where there is the potential for flooding and infrastructure damage, according to Corday.

“So we have to look farther up the watershed in the public lands and the private lands, the big ranches where there is space for the river to be natural again and to reconnect with its floodplain,” Corday says.

Funding for this type of work used to be hard to come by. But as of late, money at all levels of government has been flowing.

Programs focused on improving watershed health have the potential to access a substantial increase in federal funding from 2021-2026 through the Infrastructure Investment and Jobs Act and the Inflation Reduction Act. And in 2021, Colorado Parks and Wildlife classified beavers as a priority species, which gave beaver-related wetland and riparian restoration projects a higher priority for grant funding from the state. Even locally, some conservation districts have passed ballot initiatives to generate funds that can be applied toward improving water resources on natural landscapes, such as the Colorado River Water Conservation District’s Community Funding Partnership.

“It’s a once-in-a-lifetime slug of money,” Lenth says. “So I think that barrier is kind of in the midst of dissolving right now.”

But there is still a lack of funding for project planning, permitting and monitoring, especially in rural communities, she adds. And the permitting process for restoration work can be long––and expensive.

Once more monitoring data is available, permitting––which takes anywhere from a few months to over a year––will hopefully be expedited, Corday says.

Letting the system do the work

Melissa May, executive director of the Mountain Studies Institute in Durango, is working with a research team in southwestern Colorado––alongside members from the Mancos Conservation District, private agricultural landowners, Mesa Verde National Park, and the Ute Mountain Ute Tribe––to utilize LTPBR methods to make the Mancos watershed more resilient to drought and wildfire.

In summer 2022, the team installed beaver-inspired structures to add more complexity to the Mancos River. To their excitement, one of the structures located on a stream along private lands near Mancos attracted the attention of nearby beavers. They had hoped that the beavers would make it their home, but the structure was washed away in this year’s spring runoff.

“So, that was sort of a lesson learned. Maybe the structure would have held during a dry year. [Runoff] was just so strong this year,” she says. “We are now thinking about how much maintenance these structures will need from year to year.”

May’s team is also working with biologists from the Ute Mountain Ute Tribe to remove invasive plant species, such as tamarisk shrubs and Russian olive trees, that slurp up precious water and push out more culturally and biologically important plants such as cottonwoods and willows.

May says the goal is to let the system do the work.  “A lot of those [strategies] are focused on slowing down and spreading out the water. So instead of having one giant monsoon storm and the water just flashes right through and doesn’t seep into the system, how can you create complexity in the stream channel, where the water slows down and is able to recharge the groundwater a little bit and support these flows?”

While the retiming of flows and the potential for LTPBR projects to affect water rights is a concern for some, those at the Mancos Conservation District who are working with May and nearby landowners say that this hasn’t been an issue.

“This idea that we’re not stopping water or damming the river, we’re not stopping the flow, we’re just slowing down water and recharging the floodplain, that was important especially for agricultural [water] users,” says Sensa Wolcott, watershed coordinator for the Mancos Conservation District.

The conservation district team has been particularly cognizant of water rights, irrigation infrastructure, and the potential for landowner concerns. But the fact that they’re implementing smaller beaver mimicry projects, not massive dams, has encouraged landowners. “That has been helpful to make people more willing to try [LTPBR,]” Wolcott says.

Members of the Kawuneeche Valley Ecosystem Restoration Collaborative walk along an abandoned irrigation ditch during a tour of the valley in July 2022. Photo by Eric Brown, courtesy of Northern Water

Back at Rocky Mountain National Park, the Kawuneeche Valley Ecosystem Restoration Collaborative––which includes the National Park Service, Northern Water, the U.S. Forest Service, the Colorado River District, The Nature Conservancy, Grand County, and the Town of Grand Lake—is taking a similar approach this summer by installing beaver-like structures within Beaver Creek to slow streamflows, catch sediment, and promote vegetative growth farther from the banks.

“We’re really looking to improve the habitat, kind of the Field of Dreams approach, where if we improve the habitat in the area, then hopefully beavers will come back on their own,” says Kimberly Mihelich, a water protection specialist with Northern Water, a water conservancy district that serves eight counties in Northeastern Colorado.

The group––funded by the Rocky Mountain Conservancy, The Nature Conservancy, Northern Water, and the Colorado Water Conservation Board––isn’t looking to re-introduce beavers into the ecosystem since the environment wouldn’t be able to support them given the lack of vegetation available for them to build dams. But beavers have started to show interest.

In summer 2021, the group stumbled upon something they hadn’t seen in nearly two decades––an active beaver dam. The beaver home was nestled within a 35-acre, fenced-in restoration area in the valley that had been installed a decade ago to keep moose and elk from overbrowsing the willow trees. The fences have gaps in the bottom so small animals such as beavers can slip through.

“We were like, ‘Oh my gosh, these fences work!’” Mihelich says. “There was so, so much excitement.”

“[The beaver dam] did get washed away in some of the spring runoff,” she quickly adds. “But it was really exciting to show that if the habitat is there, beavers in the area might make it home.” This isn’t unusual, beaver dams are often damaged during large floods, but the beaver are able to rebuild if the environment can support them.

This summer, the team will install more fence enclosures to keep moose and elk from overgrazing the restoration areas and will continue using herbicides to kill off invasive plants.

Mihelich says Northern Water is involved in restoring the riparian areas because it’s a way to improve drinking water quality. The Colorado River, which winds through the Kawuneeche Valley, is part of a storage system that includes Grand Lake, Shadow Mountain Reservoir and Granby Reservoir on the Western Slope. The system has struggled with poor water quality due to increases in fine sediment loading, debris and nutrients, all of which impair water quality and can clog up water infrastructure. The system has also been impacted by recent wildfires, which are increasing in frequency and intensity due to climate change.

But restoring the riparian zones and changing the hydrology of the valley will take time, says Koren Nydick, the resource stewardship manager for Rocky Mountain National Park, especially since the damage has spanned decades.

And efforts to replace natural processes aren’t always as effective as the real thing, she adds. “We aren’t beavers. We can’t do it all,” she says. “The hope is that they come in and do it better than we could ever do it.”

Engaging agricultural communities

Lenth, the watershed restoration specialist with Central Colorado Conservancy, has been working to engage more ranchers in river restoration efforts given that agricultural producers are the largest water users in the state. Not everyone is always on board. Beavers have historically had the reputation of being a nuisance since they can cause unintended flooding of roads and plug up water infrastructure. She says it’s an easier sell for ranchers when the projects occur on summer pastures and away from any major developments.

Buffy Lenth with the Central Colorado Conservancy meets with landowners at Badger Creek Ranch near Cañon City, Colorado, where they have been collaborating on a project to restore the watershed and the riparian areas around Badger Creek. Photo by Mark Beardsley, courtesy of EcoMetrics

Lenth sees riparian restoration as a win-win: it helps make the land, and riparian areas throughout, more resilient to climate change––which can boost a rancher’s bottom line. More water held on the land means more vegetation for grazing, she says.

Lenth has been working on a riparian restoration project in the Badger Creek watershed since 2017, which covers nearly 100 square miles of the southwest portion of South Park and feeds into the Arkansas River. During thunderstorms, the creek is prone to flash flooding, which carries large amounts of sediment downstream and negatively impacts water quality. The area is a patchwork of state, private and federal lands––much of which is used for cattle grazing. Many things, including historical overgrazing, mining and hydrological droughts have caused the creek to incise, narrowing and eroding the stream channel and separating it from the floodplain. This has in turn caused the riparian area to dry out and become barren.

“We’re trying to turn that watershed into more of a water catchment, where, when it rains, we have improved plant cover and plant vigor so that we’re able to infiltrate more water, capture it and filter it,” says Lenth. “That way the water is slowed down and kept on the landscape longer to help reconnect those floodplains that have dried out over time.”

To do so, Lenth and a group of collaborators have installed natural “speed bumps”—aka small hunks of sod taken directly from the land, another beaver mimicry treatment—into the deepest parts of the creek. Collaborators include state and local government agencies, conservation districts, EcoMetrics, Trout Unlimited, conservation groups, researchers at Colorado Heritage Program and Colorado Mesa University, and private landowners. The team has also planted approximately 14,000 willows to try and slow erosion and capture more sediment and water in the process. So far, they’ve “treated” seven miles of the Badger Creek, plus five miles of tributaries, with the speed bumps.

“Wetlands are really nature’s system for cleaning, storing, filtering and conserving our freshwater, which is our most scarce resource in the West,” Lenth adds. “If you’re going to focus strategically on the most ecologically valuable lands and most important issue of our time, I really think it’s our freshwater [systems].”

One of the biggest challenges, Lenth says, is managing grazing in riparian areas when there aren’t a lot of other options for cows to get water. The team is working to encourage rotational grazing by installing more watering points across the land, as well as fences to allow landowners the ability to control the timing, intensity and duration of grazing along riparian areas.

Throughout summer 2023, researchers will be collecting data on how the project has impacted surface and groundwater levels as well as how much water is being consumed by the new vegetation to be able to better assess the impacts of their efforts. But nearby ranchers say they can already see improvements.

“It’s like night and day,” says Chrissy McFarren, co-owner of the 7,000-acre Badger Creek Ranch, which encompasses part of the watershed. “The thickness and the lushness of it. It looks like wetlands. There’s more vegetation farther out from the bank. There are more birds and insects.”

McFarren and her husband see it as their mission to leave the land and riparian areas better than they found them. In addition to participating in restoration projects, they are in the process of obtaining conservation easements for their land, and the water that runs through it, to protect it from being developed.

“We’re in that place where huge pieces of land are being turned over,” she says, referring to the amount of farmland that has been transformed into developments as farmers age and retire. “There’s not a lot of that next generation. So I think for many it is a tool for preserving and keeping land from going to subdivision.”

McFarren is inspired by the amount of collaboration she’s seeing to restore and preserve the Badger Creek Watershed and its surrounding riparian areas.

“I know there’s been a lot of collaborations in the past, but I think that’s happening more and more and I think that’s the big picture solution to climate change issues and drought,” McFarren says. “We all have to come together and work on this together. Because we’re not headed in a good direction.”

“The whole idea of like, well, just leave nature alone, let it do its thing. It’s like, well, we were part of the problem,” she says. “We need to be part of the solution.”

Legislation to pave the way for minor stream restoration projects — but not LTPBR

In 2019, Corday helped create Colorado’s Healthy Headwaters group, which included conservationists, academics, NGOs, state and federal agencies, and water stakeholders, to come up with policies and strategies to scale up riparian restoration projects throughout the state. The group influenced legislation that was drafted by DWR and later introduced by state lawmakers in April 2023 as SB 23-270. But amendments added left the bill to only include “minor” restoration projects––and removed language related to LTPBR projects.

“Those (LTPBR) projects promote a lot of ecological uplift. But those projects were the least understood and raised the most concerns for water users,” says Kelly Romero-Heaney, the state’s assistant director for water policy with the Colorado Department of Natural Resources. “And so that’s why we ended up having to amend coverage for those projects.”

The bill, which was signed into law on June 5, clarifies that minor stream alterations such as bank stabilization or restructuring a channel after it’s been damaged by wildfire or flood are presumed to not impact water rights users.

“The key [in the final bill] is there can only be an incidental amount of flooding or pooling with those structures and they can’t exceed the ordinary high water mark, so they can’t push water outside of the natural channel,” says Romero-Heaney.

For minor restoration projects defined in the bill, a person or group does not need to go to water court, obtain water rights or get a plan of augmentation, according to Romero-Heaney. Projects established before August 2023 are also “grandfathered in” meaning they are presumed to not impact water rights and can move forward.

Those who sought to amend or defeat the bill included various agricultural groups, cities, water districts, and some environmental groups.

“Their concerns are that their water rights may be injured by a stream restoration project that changes the timing in flow or increases evapotranspiration associated with the growth of trees and shrubs along the river corridor,” says Romero-Heaney, who also sits on Gov. Jared Polis’ policy team as a special advisor on water policy. “What we hear a lot is it might be ‘death by 1,000 cuts.’”

Tyler Garrett, the director of government relations for Rocky Mountain Farmers Union––a group that represents 17,000 farmers and ranchers across Colorado, New Mexico and Wyoming––told state lawmakers that his main concerns with the original bill were related to what recourse a person could seek if their water rights were impacted by a restoration project, and the amount of time they had to file a complaint or lawsuit.

“The geomorphic changes may not even be completed during this two-year window and injury may not be realized,” he said during the bill committee hearing this spring. “We also need to ensure the water right holders have time to collect the proper data and build a proper suit when they are injured.”

Romero-Heaney says it will take time for the Department of Natural Resources to interpret the new law in order to provide guidance to existing project managers and other entities interested in restoration work.

“We need to give time for the water community to have conversations around this,” she says. “So that it’s not just DNR owning this policy.”

Over the summer, Corday says the Colorado Healthy Headwaters group will continue having conversations on how to streamline the process for restoration projects in the hopes of potentially introducing another bill next legislative session to expand the existing law’s scope.

Romero-Heaney is excited to participate and help coordinate field trips for members of the water community to see process-based projects in action.

“For a lot of folks, these were novel concepts and certainly, you know, they’re looking to protect their water rights or they’re concerned about any kind of in-stream activity that could injure them,” she says.

She hopes the conversations help bridge the divide between the ecological community and the water attorneys that work on protecting water rights portfolios.

“We need projects that are reconnecting channels and floodplains and restoring the riparian corridor. We’re hopeful that the water community as a whole is open to having a conversation around that in the future,” Romero-Heaney says.

For Corday, the bill is a step in the right direction.

“It certainly wasn’t the big W that we hoped for. It was more of a little win,” she says “It’s an incremental step. And there’s more work to be done.”

Moe K. Clark is an independent journalist based in Denver. She covers topics related to the criminal justice system, environmental issues and housing/homelessness.

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