Low-tech “natural” flood management such as using natural materials to slow river flow and storing flood water on meadows will play a key role in preventing future floods, according to the chief executive of the Environment Agency.
Sixty pilot natural flood management projects have helped protect 15,000 homes and create storage for up to 1.6m cubic metres of flood water, while also helping nature recovery on 380 miles (610km) of river and on 4,000 hectares of wetlands and woodlands.
Announcing the results of the four-year natural flood management pilots, Sir James Bevan, the chief executive of the Environment Agency, said: “The warning signs of the climate crisis are stark – and sadly devastating flooding is likely to become a more familiar sight over the next century. By harnessing the power of nature alongside our traditional flood defences, we can not only help to keep communities safer, but also create wildlife havens and tackle the climate emergency.”
Natural flood management helps to slow the flow of water across the landscape via measures such as restoring meanders to canalised rivers, recreating wetlands that store flood water, and planting trees and hedges by rivers that also help absorb water.
The £15m pilot projects included Cumbrian schemes whereby farmers removed compaction in their soils to reduce water runoff, more than 100 “leaky” wooden barriers built by the Forestry Commission on streams, and a drystone wall redesigned so that it could hold water.
In Warwickshire, the community-led Shipston Area Flood Action Group built 700 leaky barriers and ponds to slow the flow of water on the River Stour during heavy rainfall, reducing the flood risk to 17 villages and towns.
In Sutton, Greater London, sustainable urban drainage systems have been installed in six schools. These systems capture rainwater runoff from surfaces like roofs, roads and pavements, preventing the drainage network from becoming overwhelmed and filtering out contaminants before the water enters drains and ultimately flows into a river.
This scheme, including planters and rain gardens built on playgrounds, is now preventing more than four hectares of hard surfaces sending rainwater into the River Wandle, helping reduce pollution in this chalk stream.
Environment minister Rebecca Pow said: “We know that flooding can have a devastating impact on people’s lives, homes and livelihoods. That is why we are investing a record £5.2bn in flood and coastal defences to ensure more communities are better prepared – and nature-based solutions are a key component of this.
“The additional benefits of natural flood management for people and wildlife are vast – helping us reach our ambitious net zero targets, providing vital new habitats and creating areas of natural beauty for people to enjoy for generations to come.”
Each natural flood management scheme in the pilot cost an average of £250,000 – far less than conventional “hard” engineering such as flood walls. “That’s on a completely different scale to most flood projects,” said Julie Foley, the director of flood risk strategy at the Environment Agency. “For the benefits, given they are so wide-ranging, that’s incredibly good value for money.”
Foley confirmed that the Environment Agency would now spend more of the £5.2bn earmarked for flood management between 2021 and 2027 on “mainstreaming” natural flood management, with a target of doubling the schemes it supports.
There were 85 partners involved in the pilot, including the Rivers Trust, Wildlife Trusts, local authorities, universities and local businesses.
The pilot project report found that involving landowners and land managers was crucial because they are responsible for maintaining the natural defences in the future.
The government’s environmental land management schemes are set to include payments to help landowners provide the “public good” of flood alleviation via such natural solutions.
Sarah Fowler, the chief executive of the Wildfowl & Wetlands Trust, one of the pilot partners, said: “Wetlands help us mitigate and adapt to the consequences of climate change, which is why WWT is calling for the restoration and creation of 100,00 hectares of wetlands in the UK.
“This report demonstrates the power of nature, and wetlands in particular, to tackle flooding. I look forward to WWT working with the Environment Agency, using our expertise in wetland science and wetland delivery, to build natural flood management solutions at scale to manage current and future flood risk.”
