As climate change leads to rising sea levels around the world, updated research from the Environment Agency reveals that nature can be an important ally when it comes to improving the UK’s resilience to flooding and coastal erosion.

For the first time, the updated directory which was first released in 2017, focuses on the role that beavers, oyster reefs, and underwater seagrass and kelp habitats can play in protecting against floods. 

Informed by significant scientific research including more than 700 papers, the directory summarises the latest evidence for 17 natural flood management (NFM) measures relating to river and floodplain, woodland, run-off, and coast and estuary management.

Interestingly, the presence of beavers which are known to build dams and channels can, according to the new directory, reduce peak flows as well as the speed of water floes, and can increase groundwater storage, connect floodplains, store carbon, trap sediment, and support other wildlife.

Dr Owen Middleton, biodiversity expert and senior consultant at Biodiversify, said: “As the UK faces increasingly frequent and severe flooding, it’s heartening to see the government embracing nature-based solutions.

“Beavers provide natural flood defences by restoring ecosystems that would also contribute to net-zero and biodiversity goals, not to mention ecotourism opportunities for local economies.

“Unlike artificial barriers that often take long to implement with long-term maintenance and ongoing costs, these natural systems evolve over time without human intervention and regenerate as nature requires them,” Dr Middleton added.

In the UK and beyond, beavers were hunted to extinction almost 400 years ago. As a result of legal protection of the species in 2022, they managed to repopulate England’s rivers but their numbers remain relatively low.

Now, more evidence is needed on how the number and locations of dams can influence flood reduction benefits, while the most effective management and maintenance techniques need to be established.

Other findings of the new assessment include that catchment woodland not only helps reduce flood risk but also provides benefits for soil, biodiversity and water quality, alongside access to nature. One study in Cumbria suggested the flow of flood water was slowed by 14-50% in woodland compared to pasture.

The latest science also showcases the significant wider benefits of saltmarsh and mudflat restoration, including their ability to store large amounts of carbon, helping to mitigate climate change. They can also filter sediments and nutrients, improving water quality.

Managed realignment at Steart Marshes in Somerset created 250 hectares of saltmarsh. A recent study showed the marsh was storing 36.6 tonnes of carbon per hectare per year following restoration, a number which compares favourably with woodland.

For the first time, the updated directory includes emerging evidence for three new measures, highlighting the potential flood risk reduction and wider benefits of coastal reefs, submerged aquatic vegetation, and beavers. There is still more to learn about these measures, including understanding what the best depth for oysters to grow and develop while also effectively reducing wave energy is.

Julie Foley, Environment Agency director of flood risk strategy and national adaptation, said: “With climate change increasing the threats of flooding and coastal erosion, we must work together with nature to boost resilience across the country. That’s why the Environment Agency is mainstreaming the use of natural flood management alongside the use of traditional engineered defences.

“Our £25 million Natural Flood Management Programme was shaped by the Working with Natural Processes Evidence Directory. Through this fund we are testing our approaches to future investment and the delivery of natural flood management.”

Dr Middleton added: “Land-use in the UK is becoming increasingly debated as the need to deliver both food security and the benefits nature can provide are priority areas for the government.

“Nature-based solutions have a huge role to play in working out how to navigate this journey, but stakeholders, especially farmers, must be part of the conversation to ensure local support, a just transition and long-term success.”

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