River Otter Beaver Trial — Wild Beaver Wetlands Cutting Storm Flows by ~30% (Devon, England)

A wild-living beaver population was discovered on East Devon's River Otter in 2014 after 400 years of absence. Devon Wildlife Trust and the University of Exeter studied it for ten years, and the animals were granted a legal right to remain in 2020.
Published in 2024, the research reports that beaver dams and their wetlands reduced storm flows by an average of ~30% in heavy rain, with an earlier Exeter site study measuring peak flows leaving a dammed section ~30% lower than those entering it. Four monitored beaver territories store about 24 million litres of water (about 6 million litres each, ~10 Olympic pools); roughly 20 family territories are estimated along the river and tributaries.
During the 2022 drought, beaver wetlands released stored water slowly and kept flows going and created refuges for species such as toads and dragonflies.
Caveats: the quantified results come from a handful of territories in one lowland catchment and may not generalise; the original source of the animals is unknown; and landowner conflicts over flooding and tree felling need active management. The programme is evidence of function rather than a payment scheme, and no carbon or wildfire effect is quantified.

Read the full analysis: https://www.devonwildlifetrust.org/news/research-backs-beavers-fight-against-flooding-and-droughts