Researchers say beaver dams reduce flood risk in Cornwall

The study found that the beaver family has significantly reduced the risk of flooding downstream since they were introduced to a farm in Cornwall five years ago.

Friday at Woodland Valley Farm near Truro, home of the Cornish Beaver Project, marks the fifth anniversary of the arrival of Chewie and Willow, who now have two kittens.

Researchers at the University of Exeter have discovered drastic changes in water flow due to dams and ponds created by new residents.
We must use their natural “superpowers” for the sustainable and long-term restoration of our wetlands.

We must use their natural “superpowers” for the sustainable and long-term restoration of our wetlands.Cheryl Marriott, Cornish Wildlife Trust

Water now passes through the site in an hour, up from 15 minutes earlier, providing more protection to the downstream village of Ladok, which is prone to flooding.

The researchers found that the beaver ponds increased the surface water supply by about 1,550 cubic meters and also increased the amount of water absorbed by the surrounding floodplain.

The height to which the stream rises after heavy rain is also 30% lower than before the beavers arrived in 2017.

Dr Alan Pattock, a researcher at the University of Exeter, said: “The results from the Woodland Valley Farm helped show that beavers can play a role in natural flood management.

“After the introduction of beavers, peak flows after heavy rains have been reduced by 33%.”

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Beaver at the Cornwall Beaver Project (Nick Upton/Cornwall Wildlife Trust)

Ecologists have found that the creation of new ponds and wetlands, as well as increased light near the water due to changes in the canopy of trees, have also contributed to the increase in biodiversity.

Ten species of birds previously absent from the site were sighted here, including the endangered chickadee, water shepherd and green sandpiper.

Hunting mice, water shrews and even a ferret have been recorded, as well as 17 varieties of dragonflies and 11 species of bats.

The beavers have also attracted the attention of visitors, and a new boardwalk was built at the site in 2022, making the enclosure now accessible to people with disabilities.

There are currently five reintroduction programs in Cornwall, but the Cornwall Beaver Project, working in partnership with the Cornwall Wildlife Trust, is calling for more releases to replicate the benefits elsewhere.

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Young Beaver Swimming (Adrian Langdon/PA)

Chris Jones, owner of Woodland Valley Farm and Community Director of the Beaver Trust, said: “We know we need to do more to cope with the natural and climate crisis, and bringing beavers back to our countryside will certainly help us do just that.

“And we need to ensure that action is taken to manage this species as its population grows.”

Cheryl Marriott, head of conservation at the Cornish Wildlife Trust, said: “After five years of habitat creation by beavers, the landscape at Woodland Valley Farm is now completely unrecognizable from its original state.

“They have breathed new life into this habitat, and their natural dam-building behavior has brought many benefits to both wildlife and people.”

She continued: “It’s amazing what can happen when you let nature take care of itself without the help of humans.

“With increasingly extreme weather events, beavers give us hope that our streams and all the wildlife that depends on them will be able to adapt to the changes. We must use their natural “superpowers” for the sustainable and long-term restoration of our wetlands.”