New research predicts California droughts will worsen



New research predicts California droughts will worsen

By Matt Weiser 10/31/2014 8:26 PM 11/02/2014 11:22 PM

Weeds and dirt were still seen under a chairlift in January 2013 at Donner Ski Ranch.Randy Pench/

Future droughts in California are likely to bite deeper and last longer than the one now gripping the state, according to new research into the potential effects of climate change. Scientists from the Scripps Institution of Oceanography and the U.S. Geological Survey used computer climate modeling tools to estimate the effects of warmer temperatures in future decades. In particular, they studied the effect on California’s mountain snowpack, the largest source of fresh water in the state, which refills thousands of water-storage reservoirs each spring via snowmelt. The results show that by 2050, the median snowpack present on April 1 each year could be one-third smaller than the historical median, and by 2100 it could be two-thirds smaller. Such a dramatic loss of snowmelt would produce less runoff to refill reservoirs each summer, potentially making droughts an ever-present condition. The research also shows that by 2100, there is only a 10 percent chance that California mountains will see a snowpack equal to the median that accumulates today. The research was conducted by some of California’s leading climate researchers, and has not yet been published or peer reviewed. It was presented Thursday at the Bay-Delta Science Conference in Sacramento.The water contained in the snowpack is declining pretty steadily through the 21st century,” said Dan Cayan, director of the California Climate Change Center at Scripps in San Diego and the study’s lead author. “According to the models, we’re already detecting these changes in snowpack.” California water management officials are bracing for these potential changes. On Thursday, the state Department of Water Resources released a revised California Water Plan, a comprehensive strategy to protect the state from water shortages and floods that looks out to 2050. A major focus involves managing the effects of climate change. “Unless we take strong action, we won’t have the existing water be reliable for the future,” said John Laird, secretary of the California Natural Resources Agency, which oversees DWR. “Over time, conservation as a way of life in California is something that simply has to be done.” State officials released the plan just days before California voters weigh in on Proposition 1, a $7.5billion water bond pushed by Gov. Jerry Brown. If passed, the measure would authorize bonds for a range of water projects, including dams, groundwater replenishment, water recycling, flood protection and habitat restoration. DWR’s water plan lays out 350 strategies aimed at boosting water supplies and improving conservation. Key among them is better connecting existing water systems. For instance, the plan calls for reconnecting rivers with their historic floodplains so that, when floods occur, the water can be held on the land to recharge groundwater wells. In many cases, this would mean breaching levees. It also could mean difficult changes in land use, said DWR Director Mark Cowin. “For many decades, one of the challenges we’ve had is that agencies that carry out responsibility for water management are not necessarily connected to the local agencies that are responsible for land use,” Cowin said. “That needs to change.” Cayan’s research into climate change would seem to support this direction… DWR’s Cowin said a broader rethinking of California water systems is needed to account for climate change as well as population growth. The state’s population, at 38million, already exceeds all other Western states combined. By 2050, it is projected to increase 30percent, to about 50million people.

Serving all those people in a warmer future would mean changing the rulebook at every reservoir, along with increasing water supplies through conservation, wastewater recycling, groundwater storage and other measures.

All this will cost money. The California Water Plan estimates the state needs to invest $200billion over the next decade simply to maintain current levels of service, and another $500billion in future decades to make improvements. Those numbers include all levels of government spending, from local water districts to the federal government. “That sends a pretty clear signal that water is going to cost more for Californians in the future,” Cowin said. “I think that’s a reality we’ll all have to get used to.”

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