The action plan, compiled by Thames Water on behalf of the General Aquifer Research & Investigation Team (GARDIT), an umbrella group of organisations concerned about the problem, identifies a five-stage solution involving 50 or more new boreholes at strategic locations across the capital. Up to 70 million litres a day will have to be abstracted by 2004.

Groundwater levels under central London are currently rising by over two metres a year, and might pose a threat to London’s subterranean infrastructure within five to ten years. The levels have risen by about 50 metres since the 1960s, following a sharp decline in industrial use of the water. London’s groundwater was used extensively by industry from the mid-19th century onwards, when levels fell by over 90 metres.

The report was unveiled on 17 March by Bill Alexander, Thames Water’s Chief Executive and Chairman of GARDIT’s Steering Group, at a meeting of business leaders hosted by the Corporation of London in the City, where groundwater levels are rising most rapidly.

Thames Water has pledged to maximise the amount used as drinking water and has invested £8 million opening up four boreholes on the outskirts of the capital to boost supplies to local customers. The company is also working to open up more drinking water boreholes in Battersea, Brixton and Islington.

Closer to the centre of London, the water is older and has a high salt content making it unsuitable for supply as drinking water, so Thames Water, in competition with other companies, is exploring alternative uses such as park watering.

The company borehole at the Millennium Dome will also mix the rising groundwater with water from the roof of the Dome to flush toilets around the site, part of Thames Water’s work to make the Dome a showcase of water-efficient technology.

Bill Alexander said: “We have worked hard to develop this solution and are keen to see it implemented as soon as possible. There is no time to waste. Though the rising groundwater threat in London is the most immediate, it is a problem affecting other cities in Britain and around the world, so we can lead the way for others to follow.”

Thames Water’s new strategy received backing from Minister for London Nick Raynsford: “Changes in London’s industrial landscape since the 1960s have led to the increase in groundwater levels. Work is already underway to address the problem and I strongly support this initiative for longer-term control. It is right that we act now before rising ground water poses a threat to our capital city.”

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