Las Vegas gambles with an uncertain water future
By LAUREN MORELLO of ClimateWire
Published: November 10, 2009 For more than 70 years, its massive walls have tamed the flows of the Colorado River, fueling the growth of cities like Las Vegas that depend on it to supply water and power from its generating station. But these days, what’s most striking is the lack of water stored behind the dam’s concrete arch. A thick white band of mineral deposits marks the walls of Black Canyon above the water line. Locals call it the “bathtub ring.” It’s where the water used to be, before the start of the current decade-long drought. For officials charged with keeping water flowing to Las Vegas and other Colorado River communities, the bathtub ring isn’t a curiosity. It’s yet another reminder that worries about climate change are reshaping their future. “Around 2002, we really began to look at whether this was one of those traditional droughts the Colorado River has experienced — or are we looking at something very different?” said Patricia Mulroy, general manager of the Southern Nevada Water Authority. Spring warming is coming earlier and harder, evaporating mountain snowpack that feeds the river and its two main reservoirs, Lake Mead and Lake Powell. “In two weeks in April, we lost the equivalent of 14 feet of Lake Powell in snowpack,” said Mulroy. “So it’s a pretty daunting and disconcerting reality that we’re beginning to get our heads around.” Mulroy is not alone. Across the United States, water managers are beginning to grapple with climate change. And it’s changing the way they think about almost everything. For the utilities that supply the nation’s drinking water, one of the first casualties is the idea that the conditions of the past can predict the future, said David Behar, deputy to the assistant general manager for water at the San Francisco Public Utilities Commission. “It’s a game changer for water managers,” he said. “It takes the variability that we understand, and can live with, and amplifies it by an order of magnitude.” …
