SOUND waves are being used to prevent fish being sucked into Thames Water reservoirs in the biggest project of its kind in the country.

An 'acoustic screen' has been installed at seven sites, including Farmoor, near Oxford, with the aim of scaring away fish and preventing them getting trapped in strong intake currents.

The £130,000 scheme, funded by the company, is part of a joint drive with the Environment Agency working with an aquatic consultant to test how well the device works.

Thames Water's reservoir manager Debbie Wrench said: "The device makes a low-pitched thud, rather like the beating of a drum.

"The noise is difficult to hear from the river bank, but can be picked up in calm conditions."

She said the design and position of each screen must be carefully calculated to ensure it is effective at keeping fish out of the intake, but does not prevent them passing along the river channel.

She said fish moving downstream tended to swim in the direction of greatest flow and the current produced by abstraction pumps could cause them to swim towards the reservoir intakes.

Adult fish are strong enough to swim away, but young ones could be sucked in.

Screens have also been installed at Datchet; Hythe End, Wraysbury and four London reservoirs.

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