As the state ends the fourth-driest water year on record with no guarantee of significant rain and snowfall this winter, Californians face the prospect of stricter rationing and meager irrigation deliveries for agriculture.
California begins a new October-September water year Wednesday with total reservoir storage at 36% of capacity, or 57% of average for this time of year. Although some private domestic wells have dried up and a scattering of isolated little communities are in danger of running out of supplies, the drought’s effect on most Californians has so far been modest. Another rainless winter would probably change that.

If 2015 is a repeat of this year, “more people will feel the direct results of the drought in our cities,” he said. Cowin expects more mandatory rationing and water-use restrictions, more unplanted cropland and greater effects on fish
and wildlife.

“I truly think the biggest impacts would be on the agricultural sector and the environmental sector,” he said.
Drops in crop and livestock production, combined with the expense of increased groundwater pumping, are expected to cost farmers $1.5 billion this year. A dry 2015 would take a $1-billion bite out of Central Valley crop revenue, according to a UC Davis report.

Officials measure dry conditions in terms of the runoff that fills rivers and reservoirs statewide and is crucial to the water supply. The lowest runoff was in water year 1977 — when statewide storage was only about a quarter of capacity — followed by the drought years of 1924 and 1931 and now 2014, according to Maury Roos, the state’s chief hydrologist.

Despite severe cuts, and in some parts of the state the total elimination of government irrigation deliveries, farmers managed to plant the vast majority of the state’s cropland this year by pumping more groundwater and buying supplies from irrigation districts with senior water rights. That would continue if the drought persists, further depleting the Central Valley’s chronically over-pumped aquifer.

“One of the reasons that agriculture hasn’t done worse this year is because of the tremendous amount of groundwater withdrawal that took place,” Cowin said. “That’s essentially borrowing on tomorrow’s future. We’ll pay that price over time.”

Even a normal rainy season wouldn’t be enough to end the drought and refill reservoirs. And although the latest forecast from the federal Climate Prediction Center gives a 60% to 65% chance that El Niño conditions will develop this fall and winter, water managers know better than to count on it.

http://www.latimes.com/science/la-me-water-year-20141001-story.html