http://www.climateark.org/shared/reader/welcome.aspx?linkid=92902

Nevada: Lake Mead Could Be Within a Few Years of Going Dry, Study Finds

Lake Mead, the vast reservoir for the Colorado River water that sustains the fast-growing cities of Phoenix and Las Vegas, could lose water faster than previously thought and run dry within 13 years, according to a new study by scientists at the Scripps Institution of Oceanography.

The lake, located in Nevada and Arizona, has a 50 percent chance of becoming unusable by 2021, the scientists say, if the demand for water remains unchanged and if human-induced climate change follows climate scientists’ moderate forecasts, resulting in a reduction in average river flows.

Demand for Colorado River water already slightly exceeds the average annual supply when high levels of evaporation are taken into account, the researchers, Tim P. Barnett and David W. Pierce, point out. Despite an abundant snowfall in Colorado this year, scientists project that snowpacks and their runoffs will continue to dwindle. If they do, the system for delivering water across the Southwest would become increasingly unstable.

“We were really sort of stunned,” Professor Barnett said in an interview. “We didn’t expect such a big problem basically right on our front doorstep. We thought there’d be more time.”

He added, “You think of what the implications are, and it’s pretty scary.”.............