With summer approaching and California's snowpack measuring a fraction of normal, state officials said Thursday they will likely order farmers and other big water users to limit the amounts they take from rivers.
The State Water Resources Control Board projected the curtailment letters would be sent out later this month for users on 10 different rivers and their watersheds. It would mark the first such directive since 1977.
Water rights holders were first alerted to the possibility of curtailments in January, when the board sent warning notices.
``When the letters do go out, they're effective immediately,'' said Timothy Moran, a spokesman for the board. ``The people who are curtailing have seven days to reply.''
The orders will be delivered first to junior water-rights holders -- those who obtained their water rights after 1914 and whose ability to take water ranks behind pre-1914 senior rights holders. Senior holders would still be able to take water initially, and would only be ordered to curtail if conditions became even more extreme.
The rare measure of ordering curtailments comes amid the third year of withering drought in California. The orders could affect supply for large water rights holders, including cities such as Sacramento, farms throughout central and northern California, and other businesses.
On Thursday, state measurements of the Sierra Nevada snowpack found more bare ground than snow. The snowpack is an essential element of California's water supply, accounting for about one-third of the state's water.
It is now at a mere 18 percent of average for the date.
``Anyone who doesn't think conservation is important should drive up the hill and take a look,'' Mark Cowin, director of the California Department of Water Resources, said in a news release.
The drought has had a ripple effect through the environment and economy.
Farmers have fallowed tens of thousands of acres and anticipate they won't have work for thousands of farmworkers. Ranchers have had to sell off parts of their herds to cut costs as free-range grasses failed to grow as abundantly as usual.
The lack of water will affect numerous species that live in California rivers and streams, home to 37 endangered fish species.
The state also has responded to twice the number of wildfires this year than usual. It has bolstered firefighting crews to prepare for what is expected to be a busy fire season through the summer and fall.
The rivers slated for the curtailment orders include the Russian River above Healdsburg and the Kern, Kings, Kaweah, Merced, Middle Fork Eel, Stanislaus, Tule, Tuolumne and Yuba rivers.
The notices will identify a time period for water users to eliminate or reduce their diversions of water. The projections range from two weeks to a month.
The board, however, does not have much enforcement staff, so its ability to ensure compliance by thousands of rights holders will be a challenge. The board will largely rely on reports from neighbors and others to find violators.
Sacramento, which holds junior and senior rights for the Sacramento and American Rivers, may be ordered to curtail diversions starting May 15, which could lead to more severe rationing, according to The Sacramento Bee.