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How Beavers Are Inspiring Efforts to Restore Degraded Rivers

December 16, 2021
In the West, conservationists, ranchers and land managers are restoring streams with techniques perfected by nature’s most diligent engineers

Caroline Nash grew up in and around western rivers. Born and raised in Connecticut, she spent long, sun-filled summers rafting the Colorado River and its tributaries with her grandfather, a Grand Canyon guide.

Days and weeks on the river would start with put-in at dawn and end with take-out miles downstream. In between were long rides in her grandfather’s van down remote desert highways, filled with stories of the region’s people and places.

Caroline Nash

It was a real-world education in the critical importance of rivers in the health of the land and communities in the West. From these early-life experiences, Caroline knew she had found her vocation.

“The running joke in my family is that – as soon as I had the chance – I moved as far away from Connecticut and as close to sagebrush as I could,” says Caroline. “I had a connection deep in my soul with the rivers – and a strong need to be on them and understand them.”

Caroline Nash (center) rows her grandfather's dory on the Colorado River at Lees Ferry in Glen Canyon National Recreation Area, Arizona.

What Caroline learned, first working on water quality projects on Oregon’s Sprague River, then as a graduate student at Oregon State University, was how “simplified” the western rivers she loved have become over the past 200 years.

As upland forests got denser and valley floor meadows eroded due to a combination of land management and development, river systems became less complex and less able to hold and store water. Wet meadows and meandering streams transformed into deep-channeled, vegetation-free gullies.

This image shows an incised channel on a degraded stream where vegetation has converted from wetlands and meadows to dry shrublands.

“The pathway a raindrop takes after it hits the ground and makes its way to the ocean used to be a lot more tortuous,” says Caroline, now an Idaho-based hydrologist and geomorphologist with CK Blueshift, a consulting firm that specializes in watershed restoration.

“Now water just moves a lot faster – and does less. It’s like putting your thumb on a hose. You just increase the speed. It's like power-washing down a valley floor towards the ocean. The water doesn't go through the redundant, repetitive cycles that create ecological benefit.”

The result: A region less able to sustain agriculture and wildlife or protect against wildfires, drought and other climate change impacts.

Looking for a solution to restore watershed health across the West, Caroline and others are drawing inspiration from one of nature’s most industrious engineers – beavers. This keystone species was nearly trapped out of existence by the early 1900s. Their disappearance and a host of other changes contributed to the damage done to riparian ecosystems.

  • Beaver Dam Restoration Big Flat after
    This image shows a stream and meadow in California's Plumas National Forest in 2006, following completion of a beaver-related restoration project. Photo Credit: Plumas Corporation
  • Beaver Dam Restoration. Before. Big Flat
    This image shows the same Plumas National Forest streambed in 1993, prior to restoration. Photo Credit: Plumas Corporation

Now, conservationists, land managers and ranchers are investing in beaver-related restoration that re-establishes structures mimicking the effects of beaver dams in degraded stream systems. These structures can create a virtuous cycle of restoration that slows down water flow, revives mountain meadows and recreates stream meanders and islands of nature. They help maintain and retain groundwater, provide natural firebreaks and refuge for wildlife, and can alleviate the impacts of post-fire flooding.

In the drought-stricken Colorado River basin, these structures and the valley floors they help restore can hold snowmelt and water higher in the watershed, helping reintroduce those redundant and repetitive cycles to create ecological benefits.

This illustration by Caroline Nash shows a design for an artificial beaver dam on a degraded stream. Beaver-dam meadows can improve a watershed's health by trapping snowmelt and releasing water more slowly, increasing available water supply and reducing flooding.

Caroline, who wrote her doctoral thesis on beaver-related restoration, applies her knowledge as a project manager at CK Blueshift, collaborating with private landowners and public land managers across the West to implement large-scale restoration efforts and monitoring programs. Her work is part of the ReBeaver Restoration Fund, a revolving fund hosted by the non-profit organization BlueCommons, which finances projects that tackle water scarcity and sustainability.

“Building structures that mimic what beaver dams do is a tool in the toolbox of solutions to fix some of these degraded streams,” she says.

In her role, Caroline designs these restoration projects, identifies appropriate sites and oversees construction. Like beavers, crews use available local materials – willows, conifers or other materials native to the valley floor– rather than haul in materials to build the dams.

Man-made structures like this beaver dam analog in south central Montana mimic the effects of beaver dams in degraded stream systems, helping restore streams, provide wildlife habitat and conserve water.

On private lands, cowboys, ranch hands and heavy equipment operators form the heart of restoration teams. “It really takes a village,” she says.

As word spreads about the benefits of beaver-related restoration, demand is increasing. In one project, Caroline is overseeing construction of more than 200 structures. Another planned project would include up to 560 structures. As new sites are chosen and construction techniques refined, restoration managers learn more about what works and what doesn’t.

“One of the most valuable lessons that we as humans can learn from beavers is persistence. It’s not just that they are great engineers, it’s that they are persistent.”

Beaver dams, like this one in Wyoming, serve as inspiration for restoration projects that re-establish small, leaky and temporary dams in degraded stream systems.

What does success look like? For some projects, it’s a return of fish and wildlife large and small, from frogs to large ungulates such as mule deer, elk or pronghorns. In others, it’s increased groundwater levels.

“Sometimes success is as simple as, like, does it look greener?” Caroline says. “It's a great measure because vegetation reflects the presence of water. Seeing wetland and riparian species emerge in places that used to only have sagebrush, or used to only have upland species, can be a really good indicator that something good is happening.”

The Walton Family Foundation is supporting BlueCommons’ ReBeaver Restoration Fund as part of its 2025 Environment program strategy, which looks to expand natural infrastructure that protects communities and water resources in the face of climate change.

I just love the land and the people. These are some of the best stewards we have to manage those landscapes.
Caroline Nash

Caroline has seen firsthand the benefits beaver-related restoration can have for people and communities. One rancher who introduced her to the concept, and has since influenced her work, began building beaver dam analogs on his property to create trout habitat so he and his kids could fish together.

“But the reason he kept doing it was that he saw massive improvements in the forage quality available to him.”

The things Caroline most loves about working on beaver-related restoration projects are the same as those she loved about traveling the West with her grandfather – learning about the culture of a region and what it takes to protect and care for a piece of land.

“If I’m completely honest, I just love the land and the people. These are some of the best stewards we have to manage those landscapes,” she says.

“It’s really meaningful to have people, especially private landowners, trust me with their hopes for a property and their vision for restoring an ecosystem. It’s gratifying to have a small hand in seeing things change in a way that benefits the environment, benefits species and benefits the people living in these places.”

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