Irrigation in Stanislaus County

Credit: Josh Viers/UC Merced

On average, California allocates more than five times the amount of water to users than is available in its rivers and streams. During times of drought, water users are increasingly scrutinized for how much water they use and how they are using it, such as to irrigate this pasture in Stanislaus County.

Water facts

  • California gives away rights to more water than it has — up to 1,000 percent in some places.
  • Researchers advocate policy updates, changes and improvement in data collection.
  • The state is working with researchers to try to sort out problems.

California has allocated five times more surface water than the state actually has, making it hard for regulators to tell whose supplies should be cut during a drought, University of California researchers reported.

Deficit-spending of the state's water supply has gone on for a century, according to an analysis by UC Merced professor Joshua Viers and postdoctoral researcher Ted Grantham, with UC Davis at the time.

The scientists said California’s water-rights regulator, the State Water Resources Control Board, needs a systematic overhaul of policies and procedures to bridge the gaping disparity, but lacks the legislative authority and funding to do so.

“It’s a broken system, from a policy perspective,” said Viers, director of the Center for Information Technology Research in the Interest of Society (CITRIS) at UC Merced. “What’s on the books shows an overwhelming disparity between resource availability and appropriation.”

Grantham, who explored the state’s water-rights database as a postdoctoral researcher with the UC Davis Center for Watershed Sciences, said the time is ripe for tightening the water-use accounting.

“Given the public’s current attention on drought and California water, we now have an unprecedented opportunity for strengthening the water-rights system,” said Grantham, now a scientist with the United States Geological Survey.

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