More than 200 fish have been rescued from Herefordshire river after a two mile section dried up completely.
The Environment Agency (EA) said the drying out of the River Dore, near Peterchurch is the worst in living memory and was probably the result of lack of rain this year in combination with the dry winters of previous years, which had stressed both surface and ground water levels.
Two miles upstream of the affected area the river is still flowing, but local geology means that the river is disappearing below ground through naturally porous rocks, so the fish were left marooned in remaining areas of standing water.
The Monnow Rivers Association said the situation was not only a danger to the fish, but to other rare animals that depend on the river such as water voles.
The EA is continuing to monitor the situation and talk to water companies that abstract water from the river, but don't believe that the river has dried up as a result of abstraction.
Welsh Water have said they do not take water directly from the River Dore and cited a report by independent consultants that found that its ground water abstraction operations had "no significant impact" on river levels.
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