In a UK first, a pioneering, large-scale project to reconnect a river to its original floodplain is underway to create a healthier, natural and more resilient place for both nature and people.

Following a successful 2019 pilot on a tributary of the River Aller on the National Trust’s Holnicote Estate in Somerset, the innovative ‘Stage 0’ approach is now being scaled up to embrace 15 hectares of the main river and its surrounding landscape. 

Inspired by successful river projects in the United States, including Fivemile-Bell in Oregon, this is the first time such a technique has been tried in the UK.

Experience in the State of Oregon demonstrates that, when river systems are restored to ‘Stage 0’, natural processes and habitats can be recovered. In many cases this leads to a slower flowing river system with multiple, smaller channels, pools, riffles and valuable wetlands that support a much richer diversity of flora and fauna. 

The US ‘Stage 0’ restoration sites have also proved resilient to the impact of the fires brought on by extreme periods of heat and drought over the past couple of years and have also provided wildlife with areas of refuge in recent wildfires.

Ben Eardley, project manager for the National Trust 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 that habitat restoration can be ‘fast-tracked’ as this woody debris helps slow flows and develop more hydrological and ecological diversity. This creates the kind of conditions that might have existed before – prior to the river system being heavily managed, with the river itself modified into a single channel. 

Floodplain wildflower seeds such as ragged robin, devil’s-bit scabious and meadowsweet will be sown over the next few weeks. And next spring, further work will enrich the habitat, including the planting of about 25,000 native trees such as willow, bird cherry and black poplar. 

Ben continues: “The river will no longer run along a single channel but form part of a complex waterscape with channels, pools, wetland and marshes. 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.”

These improvements to the riverside habitat will also support more wildlife including aquatic insects such as dragonflies, fish such as brown trout, 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.”

Dr Stewart Clarke, National Trust specialist – Freshwater, Catchments & Estuaries, said: “We are creating the best possible conditions we can for the river to adapt and respond to whatever comes its way in the face of more severe and regular floods and droughts predicted with climate change. 

“Wildlife is declining even faster in fresh water than on land or in the sea due to factors such as pollution, centuries of river modification and invasive species. Our efforts here must focus on actively adapting these landscapes to future flood and drought, recognising the floodplain as part of the river and finding the best ways to manage land beside rivers. We are embracing the latest evidence and trying out new techniques, leading the way and working with others in the adoption and promotion of ‘Stage 0’.”

The National Trust is working in partnership with the Interreg 2 Seas co-Adapt programme and the Environment Agency.  The project has been funded thanks to Interreg 2 Seas co-Adapt programme, Environment Agency, Somerset Rivers Authority (SRA), 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.”

Councillor Mike Stanton, Chair of Somerset Rivers Authority, said: “The SRA has part-funded lots of Riverlands activities on the Holnicote estate, including the successful 2019 ‘Stage 0’ pilot.  This latest project is the biggest and most exciting yet.  It offers Somerset new possibilities for reducing flood risks, improving water quality and creating bigger and better habitats for wildlife. 

“We must and will learn from this initiative with respect to other places in Somerset, and other schemes the SRA is funding.”
 
The project is part of the National Trust’s multi-million-pound Riverlands project announced in August 2018, supporting four river catchment schemes around England and Wales.  

To find out more about the Riverlands project: https://www.nationaltrust.org.uk/appeal/porlock-vale-riverlands-appeal

Photo credit: NT Images

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