Ring of fresh water [London Water Ring Main]

Thames Water is rejuvenating London´s water supply, creating a forward-looking network, with 50% more capacity, aimed at the next century. It will be based around the £250 million London Water Ring Main (LWRM)-part of a decade-long, £4 billion capital expenditure programming. Deeper than the lowest tube lines, longer than the Channel Tunnel and wide enough to take a London taxi, the 2.5 m-diameter, leakfree completed ring will be 80 km long carrying 50% of London´s water 40 m below the surface. The ring will pump water to local distribution systems, via strategically placed vertical shafts, at a maximum rate of 1295 million litres per day. The vital role of the control system is to match supply with demand at all times. The control and monitoring system has four levels which are briefly described, as is its operation