Beaver dams reduce flood risk on Cornish site, researchers say

A family of beavers has significantly reduced the risk of flooding downstream since they were introduced to a farm in Cornwall five years ago, research has shown.

This Friday, Woodland Valley Farm near Truro, home of the Cornwall Beaver Project, is celebrating the fifth anniversary of the arrival of Chewy and Willow, who now have two kits.

Researchers at the University of Exeter have discovered dramatic changes in water flow due to dams and ponds created by new residents.

It now takes an hour of water to travel through the site, compared to just 15 minutes before, giving more protection to the flood-prone village of Ladock downstream.

The researchers found that the beaver ponds increased surface water storage by about 1,550 cubic meters, as well as increasing the amount of water absorbed into the surrounding floodplain.

The creek’s elevation after heavy rains is also up to 30 percent lower than before the beavers arrived in 2017.

Dr Alan Puttock, researcher at the University of Exeter, said: ‘The results from Woodland Valley Farm have helped to show that beavers could play a role in natural flood management.

“After the introduction of beaver, peak flows after heavy rainfall were reduced by up to 33%.

The creation of new ponds and wetlands, as well as increased light near water due to changes in tree canopy, also provided a boost to biodiversity, the ecologists found.

Ten species of birds previously absent from the site have been observed there, including the threatened willow warbler, water rail and green sandpiper.

Harvest mice, water voles and even a flea have been recorded, as well as 17 varieties of dragonflies and 11 species of bats.

The beavers have also proved a big draw for visitors, and a new promenade on the site was completed in 2022, meaning the grounds can now be accessed by people with mobility issues.

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.

Chris Jones, owner of Woodland Valley Farm and director of communities at the Beaver Trust, said: “We know we need to do more to tackle the natural and climate crisis and welcoming beavers back into the countryside will certainly help us do this .

“And we need to make sure there are measures in place to manage the species as its population expands.”

Cheryl Marriott, Head of Conservation at Cornwall Wildlife Trust, said: “After five years of habitat engineering 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 humans.”

She continued: “It’s amazing what can happen when you let nature take care of itself without the need for humans to manage it.

“With the increasingly extreme weather events we’re having, beavers give us hope that our streams and all the wildlife that rely on them can adapt to change. We need to use their natural ‘superpowers’ in sustainable, long-term wetland restoration.”