Rain will lift Lake Mead water levels, but only slightly

By Joe Schoenmann

Wednesday, Dec. 22, 2010 | 12:03 p.m.

During heavy rainfall it's tempting to believe that the Las Vegas Valley's water woes have ended, that the drought is over and the multi-billion-dollar pipeline project to solve our water shortage can be halted.

Unfortunately, that's not the case.

No doubt rain is better than no rain, but Las Vegas would need a torrent of Biblical proportions to bring Lake Mead back to where it was before the drought, now in its 11th year.

As of 11 a.m. today, the Southern Nevada Water Authority estimated that about 1,400 acre-feet of rainwater had streamed into Lake Mead, a staggering 450 million gallons.

So what kind of dent will it make in Lake Mead's water level, which has fallen about 130 feet? It will raise the lake 2/10s of an inch, according to Water Authority spokesman J.C. Davis.

To raise Lake Mead the full 130 feet would take 3.5 trillion gallons of water. Forty days and 40 nights of this rain, or maybe more.

There is, however, cause for some optimism.

About 85 percent of the Colorado River flow originates with the snowpack on the western slopes of the Rocky Mountain range, and this is shaping up to be a good winter for snowpack. For much of the drought, that snowpack has been far below normal — 25 percent of normal in 2002, 52 percent in 2003 and 88 percent in 2009. And when it has been above normal, it hasn't been by much — 109 percent in 1999, 105 percent in 2005 and 103 percent in 2008.

The latest reports show the western-slope snowpack at 145 percent, Davis said.

"It's a little too early to celebrate," he said, adding that it will change over the course of the winter. "But it's a very good start."