National Trust to return rivers to their natural path to reduce impact of climate change, flood risk and to make space for nature
The National Trust is leading a pioneering project to revert rivers to their natural path before any human interference.
Allowing rivers to meander like ‘the branches of a tree’ rather than along a single channel will slow river flow, increase wildlife and tackle the impacts of climate change by holding water in the landscape.
It is the first scheme of its kind in the UK and aims to reduce the frequency of flooding, re-connect rivers to their original floodplains and increase wildlife by improving riverside habitat.
The project is being run in conjunction with Interreg 2 Seas Co-Adapt and the Environment Agency on the National Trust’s Holnicote Estate in Somerset.
Work has already started on a pilot project to return a tributary of the River Aller on the edge of Exmoor to a more natural state. The approach, known as ‘Stage 0’, will revert the tributary to its original flow before human interference, allowing natural processes to be developed.
The approach could develop a more resilient landscape better able to adapt to modern challenges like climate change and habitat loss. It also allows for more water to be stored in the water table to help in times of drought.
It works alongside nature to restore ecosystems and habitat diversity, providing a suitable home for species like the endangered water vole.
Inspired by successful river projects in America, including Fivemile-Bell in Oregon, it is the first time such a technique has been tried in the UK.
The initial project will involve 10 acres (4 hectares) of land involving a tributary of the Aller river, but, if successful will then be developed over a 33 acre (13 hectare) site on the River Aller itself.
Ben Eardley, project manager for the National Trust says: “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”
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 pilot project will use earth moving equipment, to allow natural flow, sediment and biological processes to develop a fully-connected, stream-wetland system.
After this work is complete, habitat restoration will be ‘fast-tracked’ by using woody debris and key plant species to help develop more hydrological and ecological diversity on the site.
The resulting habitat will benefit a host of plant and animal species, including the 300 water voles released by the conversation charity over the past 12 months.
Ben continues, “By making the river catchment more resilient it will become more robust and better able to cope with extreme weather events or changes in climate.”
Colin Thorne, Professor and Chair of Physical Geography at Nottingham University said, “Around two dozen streams and rivers in the US State of Oregon have been successfully restored as complex and fully-connected channel-wetland-floodplain systems known as 'Stage 0', producing remarkable benefits to river health, heritage, wildlife (including key species), sustainability and resilience.
“The outcomes of these restoration projects in Oregon coincide with the aims of the 'Riverlands' project and it is really exciting that the first 'Stage 0' restorations in the UK are now being planned and implemented at the Holnicote Estate, as part of the 'Riverlands' project."
Mark Harold, Director of Land and Nature at the National Trust said: “Rivers are arteries for water, conduits for sediments and pathways for animals that run throughout the landscape.
“The Holnicote Estate is a rich mosaic of cultural and natural landscapes and due to the combined pressures of climate change, habitat and species loss extreme weather and socio-economic challenges, we have been seeking solutions that work with and/or enhance land management approaches that result in positive changes for nature and communities.
“To make a real difference we need to be bold – to work beyond our boundaries and involve our neighbours; working with farmers and other partner stakeholders and engaging with local communities to deliver our vision for a healthy and beautiful natural environment.”
The project is also part of the conservation charity’s Riverlands project announced in August 2018, where over £14 million will be spent on seven river catchment schemes around England and Wales. To find out more about the project: https://www.nationaltrust.org.uk/appeal/porlock-vale-riverlands-appeal
B-roll footage is available of the site to include general views, aerial shots and interviews with Hilary McGrady, National Trust Director-General; Tom Matchet, National Trust Ranger; Dr Alan Puttock from Exeter University and Richard Higgs, programme manager of Riverlands at the National Trust
Images can be downloaded from: https://www.dropbox.com/sh/yzpr967p4njl8jr/AABE6VKOSCuJAe_YY5qEMmGTa?dl=0
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