As talk turns to whether California’s drought will stretch into a fourth year, two co-founders of the Center for Watershed Sciences at U.C. Davis decided to handicap it. Their conclusion: don’t bet on wet.
Jay Lund, who specializes in the engineering side of water and geologist Jeff Mount, now a senior fellow at the Public Policy Institute of California, looked at more than a hundred years of precipitation records and drought patterns in the Sacramento Valley, and calculate that the chances of another winter with below-average precipitation to be nearly three in four. Lund and Mount figure there’s about a one-in-four chance of a “critically dry” year, using the five-category nomenclature of state water managers. “There’s a good chance that if you’re in a dry year this year, you’ll be in a dry year next year,” says Lund. They write on the center’s California Water Blog:
“In all, there’s a 71 percent chance that next [water] year will be Below Normal or drier and only a 29 percent chance of experiencing an Above Normal or Wet year.
Based on 106 years of record, only 13 percent of years have been Critically Dry. But the odds facing California for next year aren’t as good. In the Sacramento Valley — the state’s largest source of water supply — there’s a 29 percent chance that the 2014-15 water year will also be Critically Dry, and a 64 percent chance that it will be Dry or Critically Dry — not favorable conditions for water management.”