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New research finds that Wildlife Trust natural flood management schemes deliver £10 of benefits for every £1 invested

Government and businesses urged to invest in beaver dams, bogs and ponds

A new report commissioned by RSA Insurance, an Intact company, and The Wildlife Trusts shows that every £1 invested in natural flood management (NFM) is expected to deliver £10 of benefits over 30 years. Nature is one of the best defences against flooding in a changing climate, but the partners behind the report believe that more investment, data and support is needed to increase its long-term positive effects.

Natural flood management means investing in beaver wetlands, creating ponds, restoring bogs, rewilding rivers and de-paving so that these areas can soak up water and hold it back in times of high rainfall*. Evidence collated by the Environment Agency shows that natural flood management is effective at reducing the overall damage from flood risk; the new report has gone further to focus on wider benefits including better habitats for wildlife, carbon storage, and improvements to health and wellbeing.

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

The new 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 & Rotherham Wildlife Trust: wetland expansion, 20 attenuation ponds created, 50+ leaky dams, de-culverted streams, 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 (high flow) conditions
  • Gloucester & 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.

Additionally, a survey of surrounding communities found that more than 85% of respondents who had access to their local scheme felt it encouraged physical health and exercise, while 92% felt they were good spaces for positive mental wellbeing and provided opportunities to see nature.

Sam Alexander Photography

Sam Alexander Photography

Kathryn Brown, director of climate change and evidence at The Wildlife Trusts, says:

“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.”

Ken Norgrove, CEO of UK & International at RSA Insurance (an Intact Company), says:

“RSA has been on the frontlines of extreme weather events alongside our customers for decades and sees the devastation they can cause. Our teams are often on the ground within the first few hours of a flood helping people, business owners, and communities recover and rebuild.

“Climate change will continue to be a defining issue of our century, so it’s important for society to prepare, adapt and become more resilient. By investing in innovative natural flood management solutions, we can help safeguard people, businesses, and the environment for a sustainable future.”

David Cadman, Head of Nature Recovery Networks at Staffordshire Wildlife Trust, says:

"In order to address flood risk in our communities, we must have more investment in natural solutions which can be used across entire river catchments to look at flooding problems holistically. In Staffordshire, we regularly use natural solutions to improve habitats for wildlife, but also to help reduce flood risk where possible. We welcome the report from RSA and The Wildlife Trusts as it confirms what we have long known - working with landowners and partner organisations to implement natural solutions can significantly off set flood risk."

Current land management practices lead to soil compaction, and ever more hard surfaces in our landscapes, meaning that water is not absorbed into the land as well as it could be and can lead to greater flooding of homes and businesses.

The report, Assessing the multiple benefits of natural flood management, recommends:

  • Improved Data and Standardisation: A standardised approach to project design, monitoring, and valuation is needed to increase investor confidence.
  • Government Support: A government-led framework, including support for private finance markets and improved data collection, is essential for increasing investment.
  • Private Sector Opportunities: The private sector, including insurers, can play a more active role in NFM investment by recognizing the broader economic and environmental benefits of NFM.

Read Assessing the multiple benefits of Natural Flood Management – summary and full report.

The Wildlife Trusts are hosting an online panel discussion, 6pm – 7.30pm on Tuesday 18th March: Could nature be our best flood defence? Join this event in person at Hull University or online via our YouTube livestream. Register here

Editor's Notes

RSA Insurance, an Intact company, and The Wildlife Trusts commissioned Stantec to write Assessing the multiple benefits of Natural Flood Management.

*Natural flood management includes:

  • Planting trees, hedgerows, woodland: to capture rainwater before it hits the ground, slow overland flow, and increase water storage below ground
  • Bringing back beavers: their activities store water in the landscape through building dams, digging channels and more
  • Creating ponds and wetlands: to collect water, and hold it in wet periods 
  • Restoring peat bogs: which can hold vast amounts of water 
  • Regenerating soils and wilder grasslands: improving soil structure allows rainfall to penetrate the surface, and rough, tussocky grasslands are more effective at storing water than intensively managed grasslands 
  • Constructing leaky dams or log diverters: to release water slowly and to move waters out onto flood plains rather than build up in a river 
  • Restoring rivers: re-engineering or modifying a river’s course to restore its natural meandering shape or to improve its ecological health mitigates high flow events 
  • Sustainable Drainage Schemes: measures to increase water infiltration in urban areas such as de-paving, ponds or vegetated ditches (bio-swales)

Evidence collated by Environment Agency: Working with natural processes to reduce flood risk 2024 - GOV.UK

For more information about the case studies examined in the report see:

Stantec

The research was undertaken by Stantec – a global leader in sustainable engineering, architecture, and environmental consulting. The project involved the review of a number of Wildlife Trusts projects, using limited data to examine a range of additional environmental and social benefits from natural flood management schemes beyond mitigating the impacts of flooding.

Natural Flood Management funding

Public funding for NFM remains a small proportion of overall flood risk mitigation. The largest current public fund in England is the Environment Agency’s £25m Natural Flood Management Programme, which is less than 1% of the total flood and coastal erosion risk management budget for the next 12-month period. Whilst a blended financial approach to NFM can be highly successful in meeting project objectives (especially for multiple beneficiaries for flood risk mitigation, or multiple benefits), current private investment in NFM is very limited. A number of barriers / challenges exist for investors engaging with NFM projects, including a lack of certainty in any market. Unless these are removed, and confidence is increased, perhaps through increased public funding, private investment will remain limited.

Leaky dams and retention ponds, Upper Sherbourne, Warwickshire

Leaky dams are made from wood (logs or trees) that are cut into short, manageable lengths and placed at right angles across a ditch or stream. They are held in place to secure them. The wood is stacked just above the natural water level so that during normal conditions the water continues to flow underneath. In high level rainfall events the water level in the ditch or stream rises and the water gets caught behind the wood. As there are tiny gaps between the wood that is stacked, the water leaks through. Hence a leaky dam as the structure slows the flow without completely preventing it. Hundreds of leaky dams are installed on ditches and streams across a landscape and the cumulative effects of slowing the flow of water result in a reduction in the 'peak flow' of the river downstream. The peak flow is the top height the water level reaches and reducing the peak flow even by a couple of centimetres can be the difference between flooding that causes damage or not.

The Natural Flood Management project involves working with landowners to identify the right solution in the right place. Sometimes the better option (or as an additional feature) is to create a retention pool. Retention pools are shallow bowls cut into the soil in key locations that act as water storage areas during high rainfall events. The rain lands on the grounds and either flows over the top or through the soils and a retention pool can intercept it as it moves downhill. Retention pools are created using diggers to scrape out the soil in a field. The soil scraped out is often put on the low side of the retention pool to create an additional lip (increasing the height and the volume of the feature and allowing it to hold more water). Retention pools drain slowly over time, releasing the water after the main extreme weather has passed and helping to reduce the peak flow further downstream. In dry spells the retention pool can become vegetated and blend into the landscape, not being obvious at all. They 'activate' when high rainfall events occur. These features can be incorporated into grass fields where livestock graze and the farmer can continue to manage the land in the way they did before.

The Wildlife Trusts

The Wildlife Trusts are making the world wilder and helping to ensure that nature is part of everyone’s lives. We are a grassroots movement of 46 charities with more than 910,000 members and 39,000 volunteers. No matter where you are in Britain, there is a Wildlife Trust inspiring people and saving, protecting and standing up for the natural world. With the support of our members, we care for and restore over 2,600 special places for nature on land and run marine conservation projects and collect vital data on the state of our seas. Every Wildlife Trust works within its local community to inspire people to create a wilder future – from advising thousands of landowners on how to manage their land to benefit wildlife, to connecting hundreds of thousands of school children with nature every year. www.wildlifetrusts.org

About RSA Insurance, an Intact company 

RSA Insurance is a multinational insurance group. We are one of the world’s oldest general insurers. We provide peace of mind to individuals and protect small businesses and large organisations from uncertainty. We use our capabilities to anticipate and improve outcomes for customers by our direct channel, our broker relationships or partner organisations. We have established businesses in the UK, Ireland and continental Europe. In 2021, the former RSA Group Plc came under new ownership and is now a wholly owned subsidiary of Intact Financial Corporation (IFC). IFC has invested heavily in building resilient communities since its inception in 2009, funding over a hundred climate resilience projects from coast-to-coast in Canada. For more information about RSA Insurance, please visit www.rsainsurance.co.uk.

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