America’s gambling mecca is facing up to some pretty unpleasant odds today. Researchers reckon the huge lake that feeds water to Las Vegas and other parts of the Southwestern United States could be dry by 2021.

They put the chance of Lake Mead suffering this fate at 50%.

“We were stunned at the magnitude of the problem and how fast it was coming at us. 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 Southwest,” says Tim Barnett of the Scripps Institution of Oceanography (press release).

In a paper in Water Resources Research they use Federal Bureau of Reclamation records of past water demand combined with calculations of scheduled water allocations and climate conditions to conclude that there is a net deficit of 1.2 billion cubic metres of water per year from the Colorado River system (PDF; subscription required). This system includes Lake Mead and supplies water to a number of cities, including Vegas.

Pat Mulroy, general manager of the Southern Nevada Water Authority, warns that 90% of that area’s water supply comes from Lake Mead (NY Times). “We have to protect our communities against the worst possibility,” she says.

In the North County Times coverage Terrence Fulp, of the Bureau of Reclamation that manages the Colorado River, doesn’t agree with the paper. He says the its studies show that Mead would be just under half full in 2021.

He told the Las Vegas Review Journal that the lake would not be allowed to run down to empty: “In my lifetime, I don’t expect to ever see it. It isn’t in anyone’s interest to see Lake Mead drained down to dead pool.”

Related

Greenhouse effect has ‘significantly dried’ the western United States – Nature, 31 January 2008

Images top: Lake Mead at Hoover Dam, October, 2007 / courtesy of Dr. Ken Dewey, Applied Climate Sciences Group, University of Nebraska, Lincoln

Image lower: map of the Colorado River basin / Scripps Institution of Oceanography, UC San Diego