Each £1 invested in natural flood management schemes is expected to deliver £10 of benefits over 30 years.

According to the Environment Agency, natural flood management is effective at reducing the overall damage from flood risk, and now fresh analysis from RSA Insurance and The Wildlife Trust uncovers wider benefits including improved biodiversity and enhanced carbon storage.

The research looked at ten natural flood management schemes created by individual Wildlife Trusts. Collectively, they had an average total cost-benefit ratio of 4:1 over ten years rising to 10:1 over 30 years. The schemes included:

• Upper Sherbourne, Warwickshire Wildlife Trust: leaky dams and retention pools installed to help stop properties and roads flooding in a suburb of Coventry

• Limb Brook, Sheffield Wildlife Trust: wetland expansion, 20 attenuation ponds created, over 50 leaky dams installed, de-culverted streams and hedge planting

• River Otter, Devon Wildlife Trust: wetlands restored by beaver dams, which can attenuate flood flows by an average of 30%, even during wet conditions

• Gloucester and Cheltenham Waterscapes, Gloucestershire Wildlife Trust: 50 homes will benefit from decreased risk of flooding due to creation of rain gardens, de-paving driveways, green verges, attenuation ponds and scrapes, which were delivered through RSA funding.

Alongside the devastating impacts that flooding can have on people, it is the UK’s most expensive natural hazard, costing approximately £2.2bn a year. This is projected to rise by 19% to 49% by the 2050s, according to the UK’s latest Climate Change Risk Assessment.

Kathryn Brown, director of climate change and evidence at The Wildlife Trusts, said: “One in six houses across the UK is currently at risk of flooding and climate change is leading to more frequent and heavier rainfall – and we know that this will become more severe in the future. The good news is our research proves that restoring natural habitats can help us tackle the effects of climate change – and in doing so, help reverse nature declines.

“The economic benefits of investing in natural flood management are clear but just 1% of the public funding for managing flood risk in England goes to natural flood management. Natural approaches to water management should be Government’s first port of call wherever appropriate – and we need to see such benefits regularly accounted for, measured and valued by both the Government and private sector in future.”

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