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Learn from Beavers about managing water in a changing environment, whether it’s drought or floods.

Learn from Beavers about managing water in a changing environment, whether it’s drought or floods.

Curved dam in a marsh, made of wood, grass and mud.

It’s no accident that both the Massachusetts Institute of TechnologyThe California Institute of TechnologyClaim the beaver (Castor canadensisThey are their mascots. Beavers are well-known engineers and can dam any stream. They can build structures with logs, mud, and even flood large areas.

As climate change causes extreme storms in some areas and intense drought in others, scientists are finding that beavers’ small-scale natural interventions They are highly valuable. Beaver ponds are useful in dry areas to restore moisture to the soil. In moist areas, their dams can help to slow floodwaters. These ecological services are so valuable that land managers have begun to relocate beavers. The U.S. The United KingdomTo restore ecosystems and make them more resilient against climate change.

Scientists have estimated that There are hundreds of millions upon hundreds of millions beaversOnce, waterways were drained across the Northern Hemisphere. They were Their fur was almost exterminatedin the 18th century and 19th centuries in Europe or North America, but are Making comebacks todayIn many areas. As a Geoscientist with a focus on water resources, I think it’s important to understand how helpful beavers can be in the Right placesTo coexist with them in the developed world.

Scientists are exploring ways to use beavers as a way to reduce wildfires and drought risks in western U.S.

How beavers alter landscapes

Beavers Dam streams create pondsThey can build their dome-shaped lodges in water and keep predators away. Many other effects are created when they create a lake.

Newly flooded trees die but remain standing as bare “snags” where birds nest. The diverted streams create complex, interwoven channels that slow-move water. They are tangled up with logs and plants that offer fish hiding places. A beaver dam’s complex structure creates many habitats for different species, including fish, birds, and frogs.

Dams are often created by humans block fish passageEven if the dams are upstream or downstream include fish ladders. But Studies have shownFish migrate upstream from beaver dams easily. One reason might be that fish can rest in slow pools after crossing the tallest dams.

The slow-moving water behind the beaver dams is very effective in trapping sediment that falls to the bottom. Studies measuring total organic matter in active and abandoned Beaver meadows indicate that active and abandoned Beaver ponds existed across North America before the 1800s. Large amounts of carbon were storedsediment that is trapped behind them. This finding is still relevant today as scientists search for ways to Carbon storage in forests and natural ecosystems can be increased.

Curved dam in a marsh, made of wood, grass and mud.

A beaver dam is located in Mason Neck State Park, Lorton, Virginia. It creates a pond that can slow down floodwaters and spread them out during storms.
Virginia State Parks, CC BY

Beavers may persist in one location for decades if they aren’t threatened by bears, cougars or humans, but they will move on if food runs out near their pond. The ponds that are left behind by beaver dams eventually drain and become grassy meadows when plants from the surrounding area seed them.

Floodplains of dried meadows can be used to flood nearby rivers. They allow water to spill out and provide habitat and spawning areas for fish, especially during high flows. Floodplain meadows may be described as valuable habitatFor ground-nesting birds, and other species that rely on the river.

The value of slowing down flow

As human settlements expand, so do the people who want to make every acre of land their own. This usually means they want land that is stable and dry enough to cultivate crops or waterways that can be accessed by boat. Humans remove floating logs from streams to create these conditions and install drains to drain water off roads and fields as efficiently as possible.

But covering more and more land surface with barriers that don’t absorb water, such as pavement and rooftops, means that water flows into rivers and streams more quickly. An average storm can bring about a torrential rainstorm that can lead to a river flow that is intense. The banks and the beds of waterways are eroded. And as climate changes Many places are subject to more severe storms because of their fuelsThis will increase its destructive effects.

This kind of flow can be stopped by some developers who use Nature-based engineering principles, such as “ponding” water to intercept it and slow it down; spreading flows out more widely to reduce the water’s speed; and designing swales, or sunken spots, that allow water to sink into the ground. Beaver wetlands are able to do all of this, but better. Research in the United Kingdom shows that beaver activity is possible. Reduce floodwaters by up to 30% on farmland.

Beaver meadows are also found in the wetlands. Help cool the ground beneath and around them. These areas have a lot of organic matter, which is a result of buried and decayed plant material. This soil retains moisture for longer than soil made from only rocks and minerals. My Wetland researchI have found that water that enters the ground after a storm passes through pure mineral sand in hours or days, but can stay in soils with 80%-90% organic matter for up to a month.

Cool, wet soil acts as a buffer against wildfires. Recent research in the west U.S. has shown that vegetation found in river corridors that have been drained by beavers is actually quite healthy. more fire-resistant than in areas without beavers because it is well watered and lush, so it doesn’t burn as easily. Areas near beaver dams are therefore a good source of food. Temporary refuge for wildlifeWhen The surrounding areas are also affected by the fires.

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Beavers need to be accommodated

Beavers’ ecological services are most valuable in areas where no one minds if the landscape changes. But in the densely developed eastern U.S., where I work, it’s hard to find open areas where beaver ponds can spread out without flooding ditches or roads. Beavers will also eat cultivated crops and can even uproot expensive landscaped trees. Soybeans and corn.

Even though flooding is often blamed upon Beavers in developed areas, Road design is often the problem, not beaverdams.. In such cases, removing the beavers doesn’t solve the problem.

Pipe in the middle of a flooded rural road

Intense rains in July 2021 carried debris overtop a beaver dam, still visible in the background, and washed out this 3-foot culvert in western Massachusetts. It has been replaced by a stronger 9-foot structure.
Christine Hatch, CC BY -ND

Culvert guards, fences and other exclusion devices can keep beavers a safe distance from infrastructure and maintain pond heights at a level that won’t flood adjoining areas. Road crossings of streams that are specifically designed to Instead of blocking fish and other aquatic animals, let them throughThese structures are beaver-friendly and can withstand extreme precipitation events and climate change. If these structures can allow debris to pass through, beavers will build dams downstream to catch floodwaters.

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Research is growing that shows that beavers are good for biodiversity, rivers, and wetland ecosystems. I believe we can learn from beavers’ water management skills, coexist with them in our landscapes and incorporate their natural engineering in response to weather and precipitation patterns disrupted by climate change.

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