By Sharon Bernstein

SACRAMENTO, Calif., May 19 (Reuters) - California's drought will cause thousands of workers to lose their jobs and cost farmers in the state's Central Valley breadbasket $1.7 billion, researchers said in the first economic study of what may be the state's driest year on record.

The most populous U.S. state is in its third year of what officials are calling a catastrophic drought, leaving some small communities at risk of running out of drinking water and leading farmers to leave fallow nearly a half-million acres of land.

"We wanted to provide a foundation for state agricultural and water policymakers to understand the impacts of the drought on farmers and farm communities," said Richard Howitt, professor emeritus of agricultural and resource economics at the University of California, Davis and the report's lead author.

As many as 14,500 full time and seasonal jobs could be lost as a result of the drought, as farmers fallow land and there are fewer crops to plant and pick, according to the preliminary study.

Altogether, 410,000 acres may be left unplanted in the San Joaquin Valley alone, the analysis showed, as farmers enter the growing season with about two-thirds of the water that they need.

By comparison, a drought in 2009 led to the fallowing of 270,000 acres of cropland and the loss of 7,500 jobs, the study showed.

"Everyone is trying to get a handle on how bad it's going to be," said Dave Kranz, a spokesman for the California Farm Bureau Federation.

Most farmers in California rely on irrigation rather than rain, many purchasing supplies from federal and state projects that pump from the San Joaquin-Sacramento River Delta. But less water than normal is available from those sources this year.

Many are turning to other suppliers or to groundwater wells on their property, Kranz said, but the study showed that pumping from wells will cost farmers an additional $448 million.

California Governor Jerry Brown, who blames the drought in part on climate change, said Monday the state would do everything possible to help farmers weather the drought.

"We're going to be steadfast in the state of California in doing everything we need to do to make agriculture work, to use our water as carefully as possible," Brown told attendees at the university's conference on climate change and agriculture in Sacramento on Monday.

To make more water available to farmers, his administration has eased some environmental protections for endangered fish, and allowed flexibility in some water rights regulations.

Our Standards: The Thomson Reuters Trust Principles.