River Aller 'set free' in major new project reconnects it to floodplain
It's hoped the newly-created wetland will help them to tackle the impacts of climate change on the Holnicote Estate on Exmoor
The National Trust say they're setting the River Aller free by doing a so-called 'reset' on the landscape here in Somerset.
The pioneering project, which has taken three years to complete, involved moving thousands of tonnes of earth to let them reconnect the river on the Holnicote Estate back to its natural course.
The conservation charity say it's hoped to reduce flooding on the 27-hectare Exmoor plain by slowing the pace of water flow.
The approach to the form of restoration has been called 'Stage 0' - which is only said to suit particular sites - but is said to reverse centuries of historical drainage, in a bid to develop 'rich and abundant refuges for nature', which not only provides a benefit to wildlife, but to people as well.
The technique was first trialled in Oregon, in the US, but it's the first time the so-called 'ctrl alt delete' approach of resetting the river has ever been attempted in the UK on such a scale.
It's reconnected the river waters with the surrounding floodplain by filling in a 1.2km managed, straightened and deepened section of the River Aller to dramatically create a new seven-hectare area of wetland.
This is helped to slow the flow of the river and hold water in the landscape - helping to combat flooding and drought, as well as tackling the impact of climate change and boosting the diversity of wildlife in the area.
Ben Eardley, project manager for the National Trust said: “At last the river can flow as it was always meant to.
“After years of research, planning and a successful pilot project, we can finally watch as the river evolves to find its own course, spilling out into the floodplain to create a rich mosaic of a wetland landscape.
“This is a hugely important moment – greatly increasing the health of our river catchments and helping them and the whole ecology of the wetlands recover and thrive.
"Everything combined will rejuvenate the surrounding landscape. It’s a win-win situation.”
Preparations for the 'transformation' have been 'meticulous', involving the local community and volunteers - who have planted 25,000 wetland trees including willow, bird cherry and black poplar.
Water voles have also been rehomed nearby, whilst fish and other aquatic species have returned.
As well as moving thousands of tonnes of earth, teams have placed 700 tonnes of fallen timber within the floodplain to provide important ‘deadwood’ habitat on which 40% of UK wildlife partially depends.
They then sowed 250kg of floodplain wildflower seeds, including wild carrot, devil’s bit scabious and meadowsweet across the site to attract pollinators.
Since the project completed at the end of July, the National Trust say 'a whole new landscape has already started to emerge' as the river channel has connected to the floodplain to form a complex waterscape with channels, pools, wetlands and marshes.
Ben added: “Despite the three years of planning, it’s been incredible to witness the significant changes already happening with wildlife literally moving back into the site straight after the work was completed.
“Through the raising of the water table it’s created the optimal conditions for an explosion of vegetation growth with the regeneration of thousands of trees alongside those we planted last winter, and water loving plant species self-seeding.
“As for wildlife benefits, we’re already seeing more of what was here before, in particular birds like house martin and wagtail and raptors such as kestrels and buzzards - but also birds that were not such as egret and heron, and amazing insects such as dragonfly.
“The work has also created the perfect conditions to attract a huge number of amphibians such as frogs and toads.
“It’s so heartening to see wildlife recover and recapture the site so quickly.
“When you think about just how much nature we’ve lost – it's projects such as these that make you realise how quickly we can make a difference and start to reverse the damage we’ve unwittingly caused our native wildlife particularly over the last 70 years.”
A number of organisations have come together to help fund this project and make it possible for the National Trust.
That includes the Interreg 2 Seas Co-Adapt programme and the Environment Agency alongside with the Somerset Rivers Authority (SRA), Green Recovery Challenge Fund and Frugi.
Careful monitoring of this project will now be carried out, in a bid to guide future floodplain reconnections in the UK and abroad.
Harry Bowell, Director of Land and Nature at the National Trust said: “More severe floods and droughts are predicted in the UK due to climate change and we must work hard now to create the best possible conditions to equip our landscapes and nature to respond.
“Our wildlife is also 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. It’s hard to comprehend but only 14 per cent of the rivers in England are in good health8.
“Urgent action is needed from everyone – especially government, government agencies, developers, water companies, nature organisations and landowners – to reverse this trend to ensure our rivers our clean and healthy, and full of wildlife once more.
“At the Trust we want to embrace the latest evidence and explore new techniques on how to make our landscapes more resilient as temperatures continue to rise – and to help tackle the nature crisis.
“Working in partnership, and at pace, with bodies such as 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: “Centuries of modifications to our river systems is one of the key pressures affecting our freshwater ecology and this will only be exacerbated by the impacts of climate change.
“Allowing our rivers to function more naturally will create new and diverse habitat for wildlife and can help them become more resilient to changes in climate.
“This pioneering river restoration technique has the potential to deliver a wide range of benefits to both people and wildlife and could be a vital tool in tackling the climate and nature crisis. The Environment Agency is thrilled to be working in partnership with the National Trust on this project and is looking forward to seeing how the site develops over the coming years.”
Councillor Mike Stanton, Chair of Somerset Rivers Authority (SRA), said: “After so many years of hard work and planning, it’s great to see this scheme flourishing. I’m delighted that we’ve helped the National Trust get to this point.
“The SRA exists to help people achieve more than they could on their own, to reduce the risks of flooding and improve Somerset’s environment, so this scheme has long been a really exciting prospect. It’s satisfying to see what a big difference it’s making already and to be learning lessons from it for other places in Somerset.”
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, visit the National Trust's website.