A novel technique to restore a river to its original state prior to any human intervention – known as stage zero – has been used for the first time at a large scale in the UK.

The method involves completely removing the channel that a river runs through and letting it reconnect to its floodplain, which it may have been historically separated from to make space for roads and railways.

“In the UK, we’ve sadly lost over 90 per cent of our wetland habitat,” said Ben Eardley at the National Trust in a press release.

The conservation charity has completed a three-year project in Somerset to restore a section of the river Aller using the stage zero technique.

The team members did this by filling in a 1.2-kilometre stretch of the river that had historically been artificially deepened and straightened. They moved 4000 tonnes of earth to fill the channel and placed 700 tonnes of fallen timber onto the site to manipulate water flow and provide new habitats in the water body.

The team also sowed wildflower seeds such as wild carrot to attract pollinators to the site. “It’s very abundant in insects, crickets, butterflies, dragonflies and birds [now],” says Eardley.

Most rivers aren’t given the room they need, he explains, but this one has now spread across multiple channels. “We’ve let the river reconnect with the surrounding landscape,” he says.

“This wetland will also hold more water during floods or drought, ensuring it’s better able to cope with extreme weather events or changes in climate, helping local communities and protecting farm businesses,” says Eardley. “It will also help improve the quality of the water by capturing and filtering the water as it runs through the landscape.”

Spot tests have shown that the water quality is already increasing only four weeks after restoration, he says, adding that the new soil environment should also sequester more carbon.

Another project in the Holnicote Estate is the reintroduction of beavers. If the project continues to be a success, it is hoped that the restored river could provide a suitable habitat for them.

Unfortunately, the stage zero technique isn’t particularly scalable in the UK right now. “Landscape scale restoration isn’t very easy to do at the moment in the UK because the regulatory and funding frameworks just aren’t there yet,” he says. “But I was with this project… we’ve learned a lot, and hopefully we can pass that learning and knowledge on and make it easier for projects like this in the future.”

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