Beavers not linked to flooding in Alyth, Scotland

Posted by Sara King BSc (Hons) MCIEEM on 22/10/2015

Beavers often get bad press for being the cause of flooding, and this is one of the key factors affecting the decision of whether to reintroduce beavers to Britain’s waterways. Heavy rain has caused flooding in Alyth Burn in Scotland, and many theories have linked this flooding to the presence of beavers in the area.

A “one in 200 year flood” occurred this summer and this caused extensive flash flooding within the village of Alyth, leaving homes without power.

There were reports that the local beaver population were the cause of the flooding, as gnawed wood was found within the flood debris. Residents were concerned that the dams created by the beavers had burst, which had incidentally cause the flash flooding.

However, a recent report has cleared the beavers and has stated that the beaver dams along the local stream network were still in place, with only minor repairs. As such, the report has concluded that beavers made little or no significant contribution to the flood.

In fact, instead of causing flooding observations by those monitoring the beaver projects indicate that beavers may reduce flash flooding by holding water upstream for longer and regulating water discharge. This could contribute towards improved future flood defence schemes at the catchment level.

Ecosulis are currently involved in a project to monitor the change in biodiversity quality as a result of beaver introduction in an enclosed site and are hoping to publish the results early in 2016. This is in co-ordination with hydrology surveys of the site which aim to assess the impact of beavers on hydrology, especially flooding.