Virtually all the UK’s rivers have been physically altered in one way or another – straightened, dammed, dredged or restrained by barriers in some way along their course.
Which is why the National Trust decided to do a radical experiment, to see if it is possible to the ecological equivalent of a complete reboot.
They filled a river in west Somerset in and let it take its own course through the landscape.
Our climate editor, Justin Rowlatt, has been finding out how the project worked out.
Producer: Harriet Bradshaw
Shoot/Edit: Gwyndaf Hughes
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