To reduce the severity of flooding in Lydbrook, Gloucestershire, England, where a 2012 flood did extensive damage, the UK Ministry of Environment released a family of beavers upstream of the village in a 6.5 ha enclosure in a publicly-owned forest. Scientists who have studied the stream believe the beaver dams could hold back some 6,000 cubic meters of water, which might otherwise gush into the village during a heavy storm. If successful, this landfill-tax-funded project is intended to be replicated elsewhere in the UK. Beavers have already been successfully reintroduced elsewhere in England and Scotland, resulting in the Scottish government listing beavers as a protected native species.
Beavers released in Forest of Dean to prevent flooding:
https://www.theguardian.com/environment/2018/jul/24/beavers-forest-dean-possible-flooding-solution
Meet the latest recruit to the UK flood defence team: the beaver:
https://www.theguardian.com/environment/2017/sep/16/beavers-uk-flood-defences-forest-of-dean
Beavers could be reintroduced to Wales after centuries absence: https://www.theguardian.com/environment/2017/jan/02/beavers-could-be-reintroduced-to-wales-after-centuries-absence