But it was only in the 1940s, after the Dust Bowl (the result of a severe drought and excessive farming in the early 1930s), that the US Geological Survey worked out that the watering holes were clues to the Ogallala, now believed to be the world's largest body of fresh water. They were about to repeat the dreams of man from the days of Ancient Egypt and Judea to turn the desert green, only without the Nile or Jordan. With new technology the wells could reach the deepest water, and from the early 1950s the boom was on. Some of the descendants of Dust Bowl survivors became millionaire landowners.'Since then,' says David Brauer of the US Agriculture Department agency, the Ogallala Research Service, 'we have drained enough water to half-fill Lake Erie of the Great Lakes.' Billions upon billions of gallons – or, as they prefer to measure it, acre-feet of water, each one equivalent to a football field flooded a foot deep – have been pumped. 'The problem,' he goes on, 'is that in a brief half-century we have drawn the Ogallala level down from an average of 240ft to about 80.'
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