Despite heavy rain at the start of the week the Exmoor villages of Allerford and Bossington in Devon escaped flooding, thanks largely to innovative work by the National Trust, project partners and farmers to restore nature and reduce flood risk in the National Park.
Since 2009, the National Trust’s Holnicote Estate has been the site of a government research project exploring how natural flood management measures can reduce flooding on the rivers Aller and Horner.
The conservation charity looks after 90 per cent of the river catchment within the 20 square mile estate.
In seven years, the National Trust and its technical partners (JBA and Penny Anderson Associates) has worked with tenant farmers to install natural flood management measures:
- Blocking ditches and creating catch-pools has helped reduce the amount of water run-off from moorland.
- Planting trees along the riverbank has slowed the progress of water.
- Riverside fields have been turned back into water meadows with the support of local farmers and five large flood storage areas (earth bunds) have been created, offering a place to temporarily store floodwater.
These have helped to slow the flow of water in the catchment, protecting the villages of Bossington and Allerford from flooding. 90 homes in the area, with an estimated insurance value of £30m, are deemed to be at high risk from flooding.
During winter storms in 2013 the large flood storage areas (bunds) reduced the flood peak by 10% on an already saturated catchment.
And when Storm Angus swept over Exmoor National Park on Monday the rivers upstream from Bossington swelled rapidly.
Nigel Hester, who has overseen the project for the National Trust, said: “We had a huge amount of rainfall in a very short period of time on Monday. It came as a surprise, with river levels rising by 50cm in just two hours. Water that’s normally crystal clear became a sludgy brown with soil washing off the fields
“But despite the rain, our natural flood defences held – helping to protect the 90 houses at high risk of flooding in villages downstream.”
Patrick Begg, The National Trust’s Rural Enterprises Director, said: “We know that planting trees and creating areas on fields to store floodwater can help cut flooding downstream. When farmers, conservationists and the Environment Agency work together to slow the flow, it can have a huge impact downstream – benefiting nature and saving the taxpayer millions of pounds.
“Over the past five years we’ve worked in partnership with our tenants to boost the natural features within the landscape which help slow flood waters when heavy rainfall hits. Their expertise has been harnessed to help with tree planting, recreating water meadows and blocking ditches, and this has resulted in a rejuvenated natural flood management system. The measures have all been integrated with the farmer’s normal business but with huge additional flood relief benefits for two local villages, both of which have been hard hit by flooding for years.
“This is one of the strongest, practical signals yet of the success of natural flood management techniques. Farmers need to be rewarded for allowing their land to be flooded. These techniques will help us all cope better with extreme weather and offer a much cheaper option than always choosing to pour money into more expensive hard defences.”
The National Trust together with think-tank Green Alliance, has proposed the creation of Natural Infrastructure Schemes, which would see farmers selling the potential of green farming in reducing the risk of flooding and reversing wildlife declines to public bodies and water companies. A report will be published by Green Alliance next week detailing how government can better support farmers and land managers to implement natural flood management schemes.
Mr Begg added: “Post-Brexit, government has the opportunity to support farmers to manage land for a full range of public benefits: wildlife, food, public access, reducing the risk of flooding and holding carbon in the soils. It’s only by changing how we support farmers that the long-term future of farming will be secured.”