Officials Friday said that for the first time ever, the State Water Project that helps supply a majority of Californians may be unable to make any deliveries except to maintain public health and safety.
The prospect of no deliveries from one of the state's key water systems underscores the depth of a drought that threatens to be the worst in California's modern history.
But the practical effect is less stark because most water districts have other sources, such as local storage and groundwater, to turn to. Officials stressed that the cut did not mean faucets would run dry.
The Metropolitan Water District of Southern California, the state project's largest customer, has said it has enough supplies in reserve to get the Southland through this year without mandatory rationing.
Even so, the announcement Friday is a milestone. "This is the first time in the 54-year history of the State Water Project that projected water supplies for both urban and agricultural uses have been reduced to zero," said state Department of Water Resources director Mark Cowin.
"This is not a coming crisis … This is a current crisis," Cowin said during a Sacramento news conference in which state officials announced a variety of actions they were taking to cope with the growing water shortage.
The State Water Project supplies mostly urban agencies centered in the Bay Area and Southern California, along with about 1,000 square miles of irrigated farmland, primarily in the southern San Joaquin Valley.
The State Water Resources Control Board is issuing temporary orders relaxing environmental standards that would have triggered increased releases from large reservoirs in Northern California. It is limiting exports from the Sacramento-San Joaquin Delta to what is necessary to meet health and safety needs, in effect eliminating delta irrigation deliveries to San Joaquin agriculture.
The board is also telling about 5,800 junior rights holders, most of them agricultural, that they will have to curtail surface water diversions in the Sacramento and San Joaquin river basins.
"Today's actions mean that everyone — farmers, fish, people in our cities and towns — will get less water," Cowin said. "But these actions will protect us all better in the long run. Simply put, there's not enough water to go around."
Last year was California's driest calendar year in more than a century of records. This year could be just as bad. Storage in major reservoirs has dropped well below average. The mountain snowpack, which acts as a natural reservoir, is at record lows for this time of year.
Gov. Jerry Brown has declared a drought emergency and urged all Californians to cut water use by 20%. The state has identified 17 communities in Central and Northern California that could run out of water in the next couple of months.
Growers who get supplies from the federal Central Valley Project will hear in a few weeks if they can count on any deliveries from that system.
About 75% of Californians' water use is by agriculture, meaning the state's fertile middle takes the biggest hit in times of drought. San Joaquin Valley farmers will pump groundwater and use any reserves they have to keep profitable orchards and vines alive, while leaving hundreds of thousands of acres unplanted this year.
Jim Beck, general manager of the Kern County Water Agency, the State Water Project's second-largest customer, said his growers would be able to make up for a large part of lost deliveries with groundwater and supplies left over from last year.
Still, he called the prospect of a zero allocation a "huge disaster that will dramatically affect our growers economically" and said it "should be viewed with the same urgency and response as an earthquake and wildfire."
In 1991, during California's last major drought, the State Water Project didn't deliver any irrigation water but sent some supplies to urban agencies. The project makes monthly assessments and, if February and March bring rain and snow, the allocation could change.
In 2010, the state project initially said it would only be able to deliver 5% of contractor requests. When winter storms boosted reservoir levels, the allocation jumped to 50%.
Officials aren't counting on that this year. By reducing dam releases now, they say they can hold on to supplies to use later for urban deliveries, to prevent delta water supplies from getting too salty and to maintain cool river temperatures for migrating salmon.
"We're trying to make sure there's enough water for fish and public health going into the future," said Tom Howard, executive director of the state water board.