California drought a 'train wreck' for Central Valley farms

David Perlman in the San Francisco Chronicle: California's great Central Valley aquifer and the rivers that feed it, already losing water in the changing climate, are now being drained because of the drought, leaving water levels at their lowest in nearly a decade.

Water experts say many farmers who depend on the huge water source beneath the valley for irrigation will have to resort to pumping water from ever deeper levels at greater costs, even as they plant crops on fewer and fewer acres as more of their land is gobbled up for development.

"The combination of climate change, growth and groundwater depletion spells a train wreck," said James Famiglietti, a water resource expert and director of the UC Center for Hydrologic Modeling at UC Irvine.

The aquifer holds water that runs into the valley from three great river systems - the Sacramento, the San Joaquin and the Tule Lake basins. It is the state's major source of stored water and is primarily used for agriculture. But over the past two years, it has lost nearly 8 million acre-feet of the precious resource, Famiglietti's research center reported last week. "That's equivalent to virtually all of California's urban and household water use each year," he said.

The Water Advisory report, which was transmitted to the California Department of Water Resources, updates a similar report published last year. Famiglietti noted that the new estimates of drought-induced losses cover only the two years between November 2011 and November 2013, but they do not take into account this winter's lack of rain and snowfall....

A 1941 picture of the All-American Canal, which transports water from the Colorado River to California's Imperial Valley