Odds improve (for now) on Las Vegas' water supply

Hoover Dam intake, July 2008
Hoover Dam intake, July 2008
Back in March I wrote about a study showing a 50% chance that climate change would leave "Lake" Mead dry by 2021. Lake Mead is the huge (or at least formerly huge) reservoir behind Hoover Dam on the Colorado River. The reservoir supplies almost all the water for Las Vegas and much of that used by milllions of people in southern California and Arizona.

Turns out that maybe things aren't quite that bad, yet. According to the Las Vegas Review-Journal, a study to be released next year will show odds of less than 5% that the lake will dry up by 2021, and of 40% it will go dry in any given year after 2050.

Bradley Udall, director of the University of Colorado Western Water Assessment and co-author of the recent findings, stressed to the Review-Journal that the outlook is still scary for water managers (and anyone who hopes to drink water in the US Southwest in the coming decades):

Even a 5% chance of a dry reservoir in any one year, it's significant, and 20% is very, very high, and 40% is off the charts with regard to making a reliable water system.

It's worth stressing here the many, many complexities and uncertainties of predicting what future emissions will be and how the climate will respond to them. So any calculation showing an exact X% chance of a dried-up reservoir in year Y should be taken with a grain of salt. But Las Vegas would be unwise to bet that the Colorado is going to be able to keep on supplying the amounts of water the desert Sin City has got used to.

Lake Mead is currently only half full (or half empty, depending on your perspective).

Read an interview here with Tim Barnett of Scripps Institution, author of the earlier study, on Lake Mead drying up and the potential impact it could have on the American Southwest.