A £15 million scheme to restore a coastal river valley to a more natural state to cope with climate change and boost wildlife has been given the go-ahead.

The Lower Otter Estuary restoration project aims to help the valley on the south Devon coast adapt to climate change and create an internationally important wildlife reserve.

The River Otter is already home to England’s first new wild population of beavers, which were given the right to remain on the waterway after a five-year trial showed their reintroduction reduced flooding and boosted other wildlife.

Now a new, largely EU-funded project will reconnect the lower reaches of the River Otter with its natural flood plain.

The scheme required planning permission, which has now been granted by East Devon District Council, with work expected to start this spring and to be completed by early 2023.

Embankments that separate agricultural land and a cricket club from the river and estuary will be breached to allow land to flood at high tide.

The move will return the valley to a more natural condition, creating around 55 hectares (136 acres) of saltmarsh and mudflats that provide habitat for wading birds, and there will also be areas of reedbed and grazing marsh.

The Lower Otter Valley has been heavily modified by humans over the past 200 years, with construction of embankments, a road, a rubbish tip, an aqueduct and an old railway line.

This infrastructure is difficult and expensive to maintain, especially in the face of climate change which is bringing higher seas, storms and storm surges, and reduces the natural flow of the water, the team behind the scheme said.

The changes, which will also involve protecting the refuse tip from erosion, raising roads and footpaths and moving Budleigh Salterton cricket club, will create a wildlife reserve of international importance within five years, they said.

Coastal communities must adapt as sea levels rise and storm events become more frequent

The River Otter has already seen a successful reintroduction of beavers, and while the changes will affect some areas where the semi-aquatic mammals have been seen, they will not be harmed, the team said.

The scheme is a partnership between landowner Clinton Devon Estates, the Environment Agency and East Devon Pebblebed Heaths Conservation Trust, which currently manages the estuary, and is supported by wildlife groups.

Mark Rice, environment manager for the Environment Agency, said: “Climate change is affecting the way we manage our coasts and estuaries and we must adapt to that change.

“The Lower Otter Restoration Project is an example of how we can do that.

“We aim to deliver long-term benefits for people and wildlife by working in partnership and through more sustainable management of the Otter Estuary.”

We're faced with rising sea levels and we've got to respond. Managed realignment like this, and restoring estuarine ecosystems is one of the ways we can do that

Sam Bridgewater, head of wildlife and conservation at Clinton Devon Estates, said: “Coastal communities must adapt as sea levels rise and storm events become more frequent.

“It is our belief the Lower Otter Restoration Project will provide a more sustainable and certain future for the threatened Otter valley.

“It will also deliver very significant benefits to people and wildlife.”

Professor Alastair Driver, director of nature charity Rewilding Britain, said it was fantastic to see the project – which he described as a “classic example of a multiple benefits project” – going ahead.

“We’ve got to tackle climate change and deal with the impacts of it here and now, as well as tackling it at source and reducing emissions,” he said.

“We’re faced with rising sea levels and we’ve got to respond. Managed realignment like this, and restoring estuarine ecosystems is one of the ways we can do that.

“It’s in effect a form of rewilding, because you’re restoring natural river and estuarine processes, and in so doing you’re going to be recovering biodiversity, and helping not only to reduce flood levels locally, but also store more carbon and improve biodiversity.”

He added that the beavers in the catchment would help restore areas to create even better and healthier wetland.