London Turns Rising Groundwater Into Liquid Asset

LONDON, United Kingdom, January 25, 2001 (ENS) - Engineers are finding innovative uses for London's rising groundwaters, including filling lakes at Buckingham Palace.

London lies in a natural basin. Water drains into the lower aquifer underneath London from the surrounding hills, the North Downs and the Chilterns.

Buckingham Palace

A 150 meter deep borehole sunk at Buckingham Palace can supply up to 2.5 million liters of water a day, some of which is used to fill the Palace lakes and water the gardens. (Photo by Ian Britton, courtesy http://freefoto.com)
For two centuries, engineering works and breweries drew millions of liters through their own wells and pumps, lowering the level of water below the ground. Levels are estimated to have dropped 90 meters (293 feet) between the mid-19th century to the 1960s.

But in the last 40 years, those industries have slowed and groundwater levels have risen by about 50 meters (162 feet).

Now groundwater levels under central London are rising by more than two meters (six feet) a year, threatening subway train stations, deep structures and the foundations of tall buildings in the capital.

Every day, London Underground, the city's subway train operator, has to pump out 27 million liters (six million gallons) of water to stop it flooding, more than four and a half million litres (one million gallons) out of Victoria Station alone.

London's subterranean infrastructure could be threatened in the next decade unless action is taken.

Almost two years ago, London's water authority Thames Water launched a five stage plan involving 50 or more new boreholes at strategic locations across London. When built, the boreholes will extract up to 70 million liters (18.5 million gallons) of water a day, thereby halting the rise, says Thames Water.

Among the more unique sites chosen for boreholes are Queen Elizabeth's London residence, Buckingham Palace, and the Millennium Dome complex in Greenwich.

A 150 meter deep borehole sunk at Buckingham Palace can supply up to 2.5 million liters of water a day, some of which is used to fill the Palace lakes and water the gardens.

map

Map illustrating Thames Water's plans to halt the capital's rising groundwater. (Map courtesy Thames Water)
"The Royal household has taken a welcome lead in developing environmentally friendly uses for the rising groundwater in the heart of the capital," said John Sexton, Thames Water's environment director.

By the end of 2001, a 135 meter borehole in Brixton, south of the Thames, is expected to provide up to four million liters a day, for use as drinking water.

"We expect that the water from the Brixton site will be of good quality, and are confident that we can treat it and use it for drinking water," said Stuart Shurlock, Thames Water's rising groundwater project manager.

Thames Water's initial 8 million investment in the plan includes other boreholes on the outskirts of London, and opening up water supply to several inner London communities.

Perhaps the most innovative use of rising groundwater was at the Millennium Dome. A borehole combined rising groundwater with rainfall from the Dome's 20 acre roof and recycled wash hand basin water to flush 177 toilets around the Dome complex.

Sadly, those toilets stopped flushing New year's Eve 2000, when the Dome closed its doors for the last time after failing to live up to original business expectations.

Millennium Dome

Rising groundwater was used to flush toilets at the Millennium Dome. (Photo by Ian Britton, courtesy http://freefoto.com)
Thames Water says it will continue to control groundwaters by using a groundwater model in conjunction with the Environment Agency to identify the most effective locations in central London for a strategic network of new control boreholes.

Set up by the 1995 Environment Act, the Environment Agency is a public body with legal duties to protect and improve the environment.

Part of Thames Water's strategy allows companies and groups to use the groundwater for private borehole sources. Water abstracted by private individuals is often used for a variety of non-potable purposes, including irrigation, cooling and other processes.