An innovative scheme to protect communities near the Exmoor National Park from flooding has won the prestigious UK River Prize.

The National Trust’s Holnicote Estate has been working with the Somerset Rivers Authority (SRA) and local farmers since 2021, looking at ways to slow the flow of the river and re-wild large section upstream of Allerford to protect around 100 homes.

More than a year on from its completion, the project has been recognised by environmental experts at this year’s awards, organised by the River Restoration Centre in Bedfordshire.

The project was the first in the UK to utilise the innovative ‘Stage 0’ river restoration technique pioneered in Oregon, USA, with the intention being to reconnect the river to the surrounding floodplain.

To achieve this, a 1.2-kilometre stretch of the river which had previously been straightened and deepened was filled in and around seven hectares of new wetlands created – the equivalent of more than ten football pitches.

In addition to filling in the river’s straightened course with more than 4,000 tonnes of earth, around 700 tonnes of fall Holnicote timber was part-buried or pinned to the ground to slow the flow of water through the floodplain.

The land now remains wetter for longer periods of time, boosting biodiversity and water storage capacity, helping the river become more resilient to extremes of weather.

Around 250kg of wildflower seeds were sown and up to 25,000 native trees – such as willow, bird cherry and black poplar – were planted on the floodplain as part of the project, which formed part of the National Trust’s multi-million-pound Riverlands initiative (with the SRA and Environment Agency also providing funding).

One of the newly formed ponds on the Holnicote Estate (Photo: View It 360)
One of the newly formed ponds on the Holnicote Estate ((Photo: View It 360))

Ben Eardley, the National Trust’s project manager, said: “We’re absolutely delighted to receive this national recognition for our work in restoring the health and resilience of the Horner and Aller catchments.

“Early results have been very promising – flood peak reductions of up to 40 per cent, longer lag times, and decreased turbidity are just a few of the indicators showing the project’s impact.”

Stewart Clarke, the trust’s national freshwater specialist, added: “Stage Zero offers huge promise for river systems rich in nature that can store water, sediment and carbon and we can create such wetland reaches within the network of more familiar single channel rivers where space allows.”

National Trust ranger at the grounds at Holnicote wich is undergoing a river restoration project.
Inspecting the newly created wetlands on a section of the River Aller on the Holnicote Estate in Somerset ((Photo: James Beck + National Trust))

Similar flood prevention and biodiversity work has been carried across 125 hectares of Tivington Farm upstream of the River Aller scheme, with several kilometres of ditches being restored and the farm reverting back to pasture from recent arable practice.

Matt Pang, the EA’s strategic planning and partnerships team, said: “Winning the UK River Prize is a huge achievement for everyone involved and reflects the tireless work and dedication of the team.”

The SRA has committed £105,000 towards a new study by the Exmoor National Park Authority into restoring the upper catchment of the River Barle, which runs from Exmoor’s northern plateau to its confluence with the River Exe between Dulverton and Exebridge.

To find out more visit www.nationaltrust.org.uk/appeal/porlock-vale-riverlands-appeal.