Stream restoration evolves to include beaver imitation, gets boost from Colorado Legislature

Over the course of two decades, David Cooper, a senior research scientist emeritus of wetland and riparian ecology at Colorado State University, returned to Rocky Mountain National Park’s Kawuneeche Valley to map 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.

David Cooper talks with members of the Kawuneeche Valley Ecosystem Restoration Collaborative during a tour of the valley in July 2022. Photo by Eric Brown, courtesy of Northern Water

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 methods, is one of dozens of such projects occurring across the state—bolstered by a recent influx of state and federal funding.

Process-based restoration, of which low-tech, process-based restoration is a subset, targets the root causes of ecosystem change with a goal of restoring a river’s natural processes.

Research shows that connected floodplains and healthy riparian areas provide valuable 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 low-tech, process-based restoration 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 last session that sought to clarify the process in order to scale up efforts across the state. The final bill was amended by those who were concerned with how the projects might impact priority water rights, so work continues to determine whether more restoration projects can be better facilitated with policy that makes them easier to permit while still protecting water rights.

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

Beaver mimicry as restoration

Jackie Corday, a land and water conservation attorney based in Montrose, has been an enthusiastic proponent of low-tech, process-based restoration since 2018, when she first saw the impact that these low-tech projects could have. “I could see the difference. It just made sense,” Corday says.

While working at Colorado Parks and Wildlife as a water resource manager, she began 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 projects in California and across the western U.S. that successfully “turned back the clock” on the damage done to 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].” By comparison, low-tech, process-based approaches can be cheaper and faster, at $50,000 to $100,000 per mile.

“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.

An example of a low-tech, process-based 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. In other cases, structures that mimic a beaver dam, called a beaver dam analog, are installed in the stream to slow the flow of water to allow it to pool and rehydrate the soil.

While low-tech, process-based restoration 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.

Low-tech, process-based restoration 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.

Legislation to pave the way for minor stream restoration projects 

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 introduced by state lawmakers in April 2023 as SB 23-270. But amendments reduced the bill to include only “minor” restoration projects—and removed language related to low-tech, process-based restoration projects.

“Those [low-tech, process-based] 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

In the meantime, Corday says the Colorado Healthy Headwaters group is continuing to have 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.

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

Progress in the Kawuneeche Valley

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 installing beaver-like structures within Beaver Creek to slow streamflows, catch sediment, and promote vegetative growth farther from the banks.

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

“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 installed more fence enclosures to keep moose and elk from overgrazing the restoration areas and continued 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.”

Fresh Water News is an independent, nonpartisan news initiative of Water Education Colorado. WEco is funded by multiple donors. Our editorial policy and donor list can be viewed at wateredco.org.

An earlier version of this article first appeared in Headwaters magazine’s summer 2023 issue.

 

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