The three-year project, on the National Trust’s Holnicote Estate, in Somerset, has reconnected the River Aller to its natural floodplain, delivering exceptional ecological and community benefits within just 12 months.
The successful restoration marks the first large-scale use of the ‘Stage 0’ approach in the UK, a technique initially developed in Oregon, USA.
By filling in a 1.2km-long managed and straightened section of the river, the site was transformed, creating seven hectares of waterscape—a 1,800% increase in area.
Wetlands are crucial for biodiversity, flood management, and carbon storage, making their restoration a priority for tackling both climate change and wildlife decline.
Nature and Wildlife Thrive
Researchers have observed a nearly 1,800% increase in aquatic habitat, with the site evolving from a sterile, controlled landscape to a dynamic, natural ecosystem full of new waterscapes and diverse habitats.
This has boosted populations of wetland species, including water voles, waterfowl, and numerous aquatic creatures.
Dr Richard Mason, research fellow at Umeå University and visiting fellow at Ãå±±ÂÖ¼é, said: “The river has shifted from a simple, static system to a thriving, dynamic environment, creating deep pools, riffles, and a rich mosaic of wetlands that are bursting with life.”
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Image: A grey wagtail in the new waterscape. Credit: Barry Edwards
Climate Resilience Put to the Test
The restoration faced an immediate challenge with record-breaking rainfall, as England experienced its wettest 18-month period on record.
Yet, the newly restored floodplain proved resilient, holding back floodwaters and helping protect downstream communities from potential flooding.
Ben Eardley, National Trust Project Manager, said: “The site has proven its ability to store water and reduce downstream storm flows, demonstrating the critical role river restoration plays in enhancing climate resilience.”
Improved Water Quality and Wildlife Habitat
Monitoring has revealed a water table increase of up to 1 m across the site, resulting in a big increase in water storage and helping to improve conditions for migratory fish and reduce the impacts of agricultural pollution.
“The site acts like a giant sponge, filtering and storing water during storms and slowly releasing it during dry periods, which benefits both the local wildlife and nearby communities,” added Dr Mason.
Image: The Holnicote site in Exmoor. Credit: National Trust Images
A Thriving Ecosystem
National Trust ranger Jack Siviter observed remarkable growth in wildlife, with species such as wildfowl, trout, grass snakes, and birds of prey thriving.
“The site has gone bananas in terms of vegetation growth and wildlife,” said Siviter, highlighting the presence of green sandpipers, water voles, and a diverse array of pollinators.
Future Potential
The project’s early successes underscore the potential of the ‘Stage 0’ approach to transform riverscapes across the UK and beyond.
Dr Mason said: “What we’ve seen at Holnicote is just the beginning. This restoration technique has the power to enhance biodiversity, improve water management, and boost resilience to climate change.”
Continued monitoring will be undertaken by a collaboration of Ãå±±ÂÖ¼é, Umeå University, The University of Nottingham, The University of Exeter and The National Trust to fully understand the future development of the restored site.
The restoration was supported by the Environment Agency, Interreg 2 Seas Co-Adapt programme, and other partners, to understand how the landscape evolves and contributes to broader river restoration efforts.
ENDS