This 31 January 2020 video from England says about itself:
How eager beavers help prevent flooding on the National Trust’s Holnicote Estate
We’ve released beavers to an area of river running through the edge of Exmoor in Somerset to help us tackle the challenges brought by climate change. The animals are “natural engineers” whose dam-building helps rivers to spread out and meander across the landscape, slowing down the passage of water and preventing flash flooding further downstream.
Beavers were once an important part of the UK’s ecosystem but they became extinct in the 16th century due to hunting for their fur, meat and scent glands. This project, approved by Natural England, will see a pair of beavers released into each of two fenced areas of woodland at Holnicote on the edge of Exmoor in Somerset. Another pair will be released at Valewood on the Black Down Estate on the edge of the South Downs.