US reservoir could be dry by 2017

The United States' largest man-made lake and reservoir could run dry in less than 15 years as a result of climate change and water demand, a study has concluded.

Researchers at the Scripps Institution of Oceanography, University of California, said that even under their most conservative estimates, they believe there is a 50% chance that Lake Mead, situated about 30 miles South East of Las Vegas, will dry up by 2021.

The reservoir, which is created by the Hoover Dam, is a key source of water for millions of people in South Western US.

Research marine physicist Tim Barnett and climate scientist David Pierce said without Lake Mead and the neighbouring Lake Powell, the Colorado River system will have no buffer to sustain the population during an unusually dry year or drought.

They concluded that human demand, evaporation and man-made climate change are creating a deficit of nearly 1m acre-feet of water per year from the Colorado River system, including the two lakes – a body of water that could supply about 8m people.

In a paper published in the Water Resources Research journal, the scientists also estimated a 10% chance that Lake Mead would be dry by 2014 and a 50% chance that reservoir levels will be too low to allow hydroelectric power generation by 2017.

“We were stunned at the magnitude of the problem and how fast it was coming at us,” said Mr Barnett.

“Make no mistake – this water problem is not a scientific abstraction, but rather one that will impact each and every one of us that live in the South West.”

The river system is currently only at half capacity following a string of dry years, and the researchers estimate that it has already entered an era of deficit.

The paper said: “When expected changes due to global warming are included as well, currently scheduled depletions are simply not sustainable.”

The pair argued that even if water agencies follow their current drought contingency plans, it might not be enough to counter natural forces, especially if the region enters a period of sustained drought or climate change occurs as currently predicted.

Kate Martin

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