Five years beavering bears water for ecologists

Landowner Spains Hall Estate in Braintree collaborated with engineering consultancy Atkins, aided by funding from the Environment Agency and Essex and Suffolk Water, to release the first pair of beavers in the area for centuries, based around a 10-acre woodland stream.

The estate was seeking a means to store rainfall and high river flows, both for ecological improvement to protect a local village from floods.

The animals, now 11-strong, created nine dams that are estimated to store 3 million litres of water in ponds covering almost a quarter of the woodland.

Environmental scientist at Atkins Emily Brown said: “We took the approach that if you treat the whole farm as a reservoir, you could identify elements and zones in the landscape that could store water and, with the proper management, release that water when it is most needed.” 

She said initial study results suggested a 5-10% increase in river flows during summer months, where there would normally be drought. In winter, she said, the measures could lower the risk of local flooding by between 15-30%.

Spains Hall Estate manager Archie Ruggles-Brise said data collected by King’s College London demonstrated that the way water flowed across the farm had changed, with the beavers increasingly building bigger dams to trap more water each time it rains. These changes enabled storm water flowed downstream more slowly, helping alleviate low river water levels in summer.  

Atkins’ subsidiary AtkinsRéalis documented the changes and used digital tools to record details, explained assistant environmental scientist Molly Howell: “It’s a great example of how we’re able to use digital tools within a natural environment to enhance our understanding of what’s happening on the ground, and use that data to better inform how we support the project.”

The EA’s catchment manager Matt Butcher said the work demonstrated that nature-based solutions could tackle challenges in smaller river catchments that after supporting the pilot study the agency had been convinced to give more direct support with partners to enable construction of two larger beaver enclosures.

Estate manager Ruggles-Brise added: “This is a massive milestone for us. We took a chance 5 years ago that bringing beavers back would be beneficial, and it’s proven to be better than we could ever have imagined.”

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