A PIONEERING project to reconnect a river to its original floodplain is underway in Somerset following a successful pilot scheme.
The National Trust is leading the large-scale restoration, which is the first of its type in the UK.
The project on the trust's Holnicote Estate, Exmoor, comes after a successful trial run on a tributary of the River Aller.
The approach, called ‘Stage 0’, is now being scaled up to 15 hectares of the main river and its surrounding landscape.
Ben Eardley, National Trust project manager, said: “We now have a tried and tested method to start reversing the damage done to our rivers.
“‘Stage 0’ floodplain reconnection completely resets natural processes – it’s like the ‘ctrl, alt, delete’ equivalent of a computer reset - and lets the river decide what it wants to be.
“By seeing the river and its surrounding landscape as a whole, we can build resilience and boost biodiversity.”
The first stage of the project is underway, with careful earthworks creating shallowly skimmed areas to reset the valley bottom and natural river flow.
Large timbers have been pinned or partially buried into the floodplain so habitat restoration can be ‘fast-tracked’, as the wood debris helps slow flows and develop more hydrological and ecological diversity.
This creates the kind of conditions that might have existed before the river system was heavily managed.
Floodplain wildflower seeds uch as ragged robin, devil’s-bit scabious, and meadowsweet will be sown over the next few weeks.
Further work will be carried out to enrich the habitat in the spring, including the planting of about 25,000 native trees.
“The river will no longer run along a single channel but form part of a complex waterscape with channels, pools, wetland and marshes,” said Ben.
“This helps slow the river flow to help combat flooding and drought events as well as well as increasing wildlife and tackling the impact of climate change by holding water in the landscape.
“By creating these new wetlands, they will not only hold more water during floods or drought but also effectively store carbon.
“So, the river catchment will be better able to cope with extreme weather events or changes in climate. And it also rejuvenates the surrounding landscape.”
The improvements to the riverside habitat are expected to support more wildlife, including aquatic insects, fish, grass snakes, birds, bats, water voles, and otters.
Ben added: “Careful monitoring of this pioneering project will guide future floodplain reconnections in the UK and abroad. It’s a nature-based solution that you can literally see in action.”
The National Trust is working in partnership with the Interreg 2 Seas co-Adapt programme and the Environment Agency.
Other sources of funding are the Somerset Rivers Authority, the Green Recovery Challenge Fund, And Frugi.
Harry Bowell, director of land and nature at the National Trust, said: “This innovative work to explore techniques on how to make our landscapes more resilient to climate change is absolutely critical as we tackle both the nature and climate crisis, over the coming years.
“Working in partnership, and at pace, with bodies like the Environment Agency is exactly what we need to be doing more of as we face into these challenges.
“This project is a fantastic example of how this can be done through our collaborative efforts.”
Matt Pang, Environment Agency catchment coordinator, said: “The Environment Agency is really excited to be involved in the work being delivered by the National Trust across the Holnicote Estate.
“The River Aller Floodplain Reconnection scheme allows us to test the new ‘Stage 0’ river restoration concept at a larger scale.
“It should achieve a range of outcomes for the environment including increasing habitat diversity and biodiversity, reducing flood risk for downstream communities, and making the river more resilient to the impacts of climate change.
“We hope this project as a whole will significantly contribute towards achieving targets for nature recovery and climate change at a landscape scale, and provide vital evidence towards restoring natural processes in our river systems.”
The project forms part of the National Trust's multi-million-pound Riverlands project, announced in August 2018.
To find out more about the Riverlands project, visit www.nationaltrust.org.uk/appeal/porlock-vale-riverlands-appeal.
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