The footpath along the dam at Pitsford Reservoir will be closed for about four weeks from Monday as part of a £750,000 project to install three new pipes.
The project will enable Anglian Water to rapidly reduce the amount of water in the reservoir if it is ever required in the future.
Steve Parker, project manager for Anglian Water, said: “We’re installing three pipes. Each one is 100 metres long and 24 inches wide and together they will be able to suck 5,000 litres per second out of the reservoir, doubling the current rate at which water can be pumped out.
“Once complete, it would be possible to drain 50 per cent of the reservoir – some eight billion litres of water – in less than three weeks.
“While it is incredibly unlikely that we’ll ever have to rapidly pump water out of the reservoir, it’s important we would be able to do it safely if it were ever needed. It’s an essential part of the management responsibilities we have to fulfil when we are in charge of a large body of water.”
A temporary footpath will be in place while the dam is closed.
Work got under way at the start of March underneath and alongside the dam to install supporting power and vacuum pipework.