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they modify their traditional plan- ning framework to account for climate change, which is much more uncer- tain, and there’s not a lot of consensus about,” said David Groves, senior policy researcher with the RAND Corporation.

Groves, who has worked with major water utilities and the Depart- ment of Water Resources (DWR) in addressing climate change, said water managers should consider the range of plausible impacts “without worrying initially about how likely those impacts are, because we don’t have a lot of information about that, and it’s highly contentious.

“Once we understand our vulner- abilities and options for reducing them, the water community can then have an informed dialogue over likelihoods of the impacts and the tradeoffs in ad- dressing them,” he said.

Adapting to warming temperatures and increased demand means ramping up water recycling and water conser- vation along with looking at pursuits such as desalination and importing water from other basins, which Groves acknowledged can be “very diffi cult and contentious projects.”

Planning for climate change means expecting dry times to happen, a prac- tice ingrained in water agency plan- ning. In Tulare County, the Kaweah Delta Water Conservation District has more than 40 recharge basins covering about 5,000 acres to capture fl oodwa- ters for storage, something that will be useful if more precipitation falls as rain instead of snow.

“Everything we have been doing to try and capture those fl oodwaters goes right along with the scenario for best managing a climate change situation,” said Mark Larsen, general manager for the district. “It gives us more encour- agement to keep going in that same direction.”

Studies from an array of respected institutions all point to a warmer and drier West. Writing in The Sacramento Bee June 23, Roger Bales, director of the Sierra Nevada Research Institute at UC Merced, and senior researcher

July/August 2013

Norm Miller described a forthcoming hydrologic system unlike the pattern California has experienced in modern times.

“The shift from snow to rain in the Sierra Nevada, decreased snow cover area, coupled with longer growing seasons, are certain to result in more winter stream fl ow and less summer stream fl ow, impacting water deliveries during the growing season,” Bales and Miller wrote in “How Climate Change May Affect Californians,” a series of responses to Rep. Henry Waxman, D-Los Angeles. “This loss of snowpack storage will reduce water security for California.”

Researchers with California State

University, Fullerton and the Universi- ty of Southern California say the region faces “a perennial freshwater availabil- ity crisis.”

“Climate models predict a drying of the American Southwest, includ- ing Southern California, over the next century,” said Matthew Kirby, associate professor of geological sciences with CSU Fullerton and lead author of the paper “Latest Pleistocene to Holocene hydroclimates from Lake Elsinore, California,” in the Sept. 15 edition of the journal Quaternary Science Reviews. The Colorado River is the primary water source for 35 million people in the U.S. and the Republic of Mexico. Studies based on different climate change scenarios say the river’s fl ow will decline by 2050, with the estimates ranging from less than 10 percent to 45 percent.

The different estimates “have led to a lot of frustration,” said Julie Vano, lead author of “Understanding Un- certainties in Future Colorado River Streamfl ow,” published in June in the Bulletin of the American Meteorological Society. “This paper,” she said, “puts all the studies in a single framework and identifi es how they are connected.” The paper says “despite indications of consensus of climate models regard- ing future drying, there is still consider- able variability in future climate projec- tions.” As an example, a recent study by the Bureau of Reclamation found

“Once we

understand our vulnerabilities and options for reducing them, the water community can then have an informed dialogue over likelihoods of the impacts and the tradeoffs in

addressing them.” – David Groves, RAND Corporation

Hear more from David Groves

Watch a segment from the Water Education Foundation’s “A Climate of Change” video


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