Exmoor river 'reset' aims to cut flood risk and bolster wildlife

Pioneering work to return a river to its natural path in an attempt to improve the diversity of flora and fauna and reduce the risk of flooding has been launched on Exmoor in Somerset.

The scheme, the first of its kind in the UK, has been inspired by projects in the north-west of the US, in which rivers and streams have been encouraged to flow through multiple channels, pools and shallow riffles as they would have done before mankind arrived and began moulding them into shapes to suit farming and settlement.

Diggers have begun to move earth around on a spot on the National Trust’s Holnicote Estate called Mud Pool Meadow through which a tributary of the River Aller flows.

The idea is that rather than running along a single channel the water will be able to find its own way and meander through the landscape more in the shape of the branches of a tree. It should lead to more areas of wetland and natural pools and streams.

Though the National Trust scheme is in its infancy, peregrine falcon and deer have already been spotted returning to the spot, and the hope is that wading birds such as the curlew will be tempted to the site. It should also help a population of water voles that have been re-introduced to Exmoor.

Like much of Exmoor and other uplands in the English West Country, land has been drained and rivers and streams managed to maximise land for grazing.

The idea at Mud Pool Meadow is to “reset” nature and give the water a chance to move and settle in a more natural way.

At the moment the digging work means that much of the area is bare earth but trees such as alder and willow are expected to gain a foothold soon.

The project is inspired by the Fivemile-Bell restoration scheme in Oregon, where work has been done on rivers and streams to restore them to how they were before settlers drained the land. One effect there has been to significantly increase the number of salmon in the waterways.

Exmoor’s version is on a much smaller scale, initially covering 10 acres. If it works it will be developed over a 33-acre site on the River Aller.

Ben Eardley, a project manager at the National Trust, said: “Many streams and rivers have become disconnected from the surrounding landscape through years of land drainage and mechanised flood control.

“Conventional river restoration projects typically ‘re-meander’ straightened streams, working on the assumption that these streams were single channelled before human interference. But there is strong evidence that prior to disturbance many watercourses naturally flowed through multiple branching channels, a bit like the branches of a tree.

“Over hundreds of years we have simplified and concentrated rivers into a single, straight channel that has over time become disconnected from the land around it. Instead of storing water and depositing sediment, and recharging groundwater aquifers, these modified systems move water and sediment rapidly through the catchment, providing no buffer against floods, droughts or valuable top soil loss.

“With an increase in flooding and droughts predicted through climate change we need to make our landscapes more resilient to these challenges.”

The scheme is being run in conjunction with “Interreg 2 Seas Co-Adapt” – a European programme covering England, France, the Netherlands and Belgium – and the Environment Agency.

It is also part of the National Trust’s Riverlands project, which will spend more than £14m on seven river catchment schemes in England and Wales.