Monday, July 23, 2007

A dry-weather crisis for Hoover Dam


HOOVER DAM, Ariz.--To get a sense of what seven years of drought in the Colorado River basin looks like, all you have to do is gaze out at Lake Mead from the top of the dam here and view the 108 feet of brightly colored earth below the familiar red walls rising from the water.
Lake Mead is 108 feet below its traditional level, the result of the many years of low rainfall, and these dry years could soon have some serious effects on the region.
I visited Hoover Dam on my Road Trip around the Southwest and was given a behind-the-scenes tour by Robert Walsh, the external affairs officer for the lower Colorado region of the U.S. Bureau of Reclamation, which manages the dam.
And Walsh was not in an optimistic mood.
He explained to me that while there have been several severe droughts in the dam's history--including one that lasted 12 years in the 1950s, as well as some in the 1970s and 1980s--this one is more serious because the population in the region has exploded, due in large part to the tremendous growth of the Las Vegas area.
Now, Secretary of the Interior Dirk Kempthorne, who has legal control over the dam, has mandated that the Bureau of Reclamation come up with a plan for how to deal with potential shortages in available water for California, Nevada and Arizona, should continued low rainfall eventually mean that the Colorado River--and thus Hoover Dam--not be able to meet those states' water demands.
The problem, Walsh said, begins with the 7.5 million acre-feet of water allotted to the lower Colorado River basin region under the Boulder Canyon Act enacted by Congress in 1928. Every year, the river has been able to provide Arizona, California and Nevada with that much water--or more--but it is beginning to look like there may be a shortfall in the future if the drought doesn't end.
Ironically, in the 1990s, the basin had a surplus of water, and Reclamation began to work on guidelines for how to share the extra water. The guidelines were completed and implemented in 2000, according to Walsh, just as the drought began.
The situation is actually quite complex, it turns out, and has to do with the interior secretary's annual responsibility to make a determination of whether there is a surplus, a shortage or a normal supply of water.
And now that it looks like we're in for the first shortage year, the secretary has demanded that Reclamation have a plan ready by this winter.
What seemed to me to have Walsh--and presumably many others--pessimistic is the sense that the likely scenario would be to come up with a plan that mandates stretching the existing supply out as long as possible, which means drawing supplies from the water table, something that can never be replaced.
Of course, one option could be to demand severe conservation on the part of southern Nevada, southern California and Arizona--the constituencies of the Lower Colorado River basin region--but who can imagine that happening?
Walsh said that all those constituencies recognize that the circumstances surrounding the river--and its water production--have changed since the dam was opened in the 1930s, and that the states understand that they have to work together to solve the serious problem that could come from continued drought and presumably water shortage.
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Yet, no one knows how to solve the problem.
Reclamation has come up with a complex matrix of possible scenarios (click here for PDF), and we may see the bureau demand some of those be implemented when it makes its determination of what to do in the case of a shortage in December.
It does appear that conservation is part of the bureau's preferred plan, and that would be good.
But judging from Walsh's assessment, it's not necessarily a bright future for the region. Droughts do come and go, but water demand is only going up, and over time, it seems certain that the region is going to need more water than is available.
And unless it comes up with some way to drastically alter its water use, the future is a more than a little scary.

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