The falling levels of the two large reservoirs in the southwestrn United States, Lake Powell and Lake Mead, have become the de facto index of the water problems of the West. Today, that index triggered a landmark government response.
For the first time in its four year history, the Bureau of Reclamation will reduce the annual release of water from Lake Powell by nearly 10 percent. The quantity of water has always been a critical piece of the system that supplies seven Western states and Mexico. Now, after the 14 driest years on record, that amount will drop to 7.48 million acre-feet.
“There’s a lot of folks downstream that are very concerned,” said Doug Kenney, director of the Western Water Policy Program. “And the users downstream are places like Las Vegas, Los Angeles, San Diego.”
The reduction will not immediately impact the downstream states of Arizona, Nevada, and California. However, the chance that such reductions will be made is now roughly 50 percent for 2016, according to the Bureau.
“Right now we have about 2 million people in the valley and we are pretty much using all of our share,” says Sajjad Ahmad, a civil engineer at the University of Nevada-Las Vegas who has used global climate models to study the water future of Las Vegas and the valley it lies in. "We do have a problem” he says.
While Nevada’s share of the Colorado is relatively small, the growing urban area has little to spare. The general manager of the Southern Nevada Water Authority, Pat Mulroy, has recently discussed seeking federal disaster relief.
While all the Western states have been preparing for shortages for years, to make supply and demand meet will require changes.
“Roughly a third of the Colorado River is growing alfalfa and pasture and forage crops,” says Michael Cohen, senior research assistant at the Pacific Institute. “They’re very water intensive crops and they’re not directly consumed.”
With low flows in the Colorado River accepted as the “new normal,” water-intensive agriculture and rapidly growing cities can only coexist if they become more efficient through reuse and conservation—or if they find new sources of water.