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Let the river flow: crossing the banks of Tamar, a boon for the fauna and the climate | Cornwall

Herons and little egrets have already started hunting in the muddy shallows and the hope is that within a few years more rare waders such as curlews and mammals including otters and harvest mice. will appear.

But the plan to allow water from the River Tamar, the iconic border between Devon and Cornwall, to return to a piece of land that was turned into farmland in the Victorian era, is far more than enticing wildlife.

In addition to being good for flora and fauna, the rich wetlands that are created will trap carbon, help clean up the river by trapping sediment, and alleviate flooding when storms arrive from the Atlantic.

The National Trust’s £ 250,000 Cotehele Quay project, once a thriving port and boat building base, is the first in a series planned along the banks of the great river.

“It’s about giving the river space,” said Alastair Cameron, project manager at the National Trust, as he watched the 1.7 hectare site gradually fill with a mixture of water. salt and freshwater as high tide approaches.

An aerial photo of the successfully flooded site.
An aerial photo of the successfully flooded site. Photograph: Steve Haywood / National Trust / PA

The Victorians reclaimed the area from the river in the mid-19th century, building a heavy embankment to keep water out and graze animals. In recent years, the climate emergency and extreme weather events made it more difficult to defend the embankment and flooding was common.

Earlier this year, the trust, backed by the Environment Agency, Natural England and the University of Plymouth, dug three canals through farmland and then this month dug a 15-meter-wide breach in the embankment to let the water run out at high tide.

When the water arrives, the ditches turn into swampy streams. “It was a good time to let the water in,” Cameron said. “It’s a fairly simple but effective project. Now it’s about letting nature take its course.

The team were delighted that within days the herons, egrets and mallards had been spotted. Over the years, reed beds are expected to form and other birds that should appear in time include shelduck shelducks, king prawns, ducks and teals. Salmon fry and elvers can find refuge in streams.

Tony Flux, Coastal and Maritime Advisor in the Southwest for the National Trust, said the project was an example of the charity’s “shifting shores” program, which involves working with rather than fighting the elements.

Work to breach the bank in Cotehele.
Work to breach the bank in Cotehele. Photograph: Steve Haywood / National Trust / PA

“Working with nature rather than against it is a more sustainable and long-term solution – and is much less expensive than a continuous cycle of construction and repair, which will only increase in frequency as our climate changes.” , did he declare. “Continuing to repair the old embankment would have been a never-ending task.

“The work we are doing will allow the river to behave much more naturally and adapt to the changes occurring in our coastal and estuarine areas, which are invariably the first places to feel the impacts of climate change. “

A project similar to the Trust’s Cwm Ivy, where the decision was made not to repair a dike after it was breached during storms in 2013-14, resulted in a spectacular, wildlife-rich area that attracted curlews and even a passing osprey. .

The Cotehele Breccia is the first of three on this stretch of the river. The other two projects are led by the Environment Agency. Water is to be allowed to enter larger areas upstream from Calstock village next month and downstream to South Hooe in the spring.

Rob Price, watershed coordinator for the Environment Agency, said that over decades the projects could result in the sequestration of several thousand tons of carbon. He said three more sites on the Tamar were being assessed and other rivers in Cornwall and Devon could benefit from the same type of project.

Price admits he felt moved when he first saw the water flow back to the land from which it was banished nearly 200 years ago. “We are allowing the river to reclaim the land taken from it,” he said. “It’s a great time for the Tamar.”

theguardian Gt

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