November 11, 2013

San Joaquin Valley groundwater levels falling at rapid rate

San Joaquin Valley’s groundwater is being depleted at an alarming rate and something needs to be done before it’s too late, state officials were warned this week. Groundwater reserves are shrinking by 800 billion gallons per year in the Central Valley, which is enough water to sustain 22 million people.

San Joaquin Valley’s groundwater is being depleted at an alarming rate and something needs to be done before it’s too late, state officials were warned last week.

Here’s a scary statistic: Groundwater reserves are shrinking by 800billion gallons per year in the Central Valley.

“At 100 gallons per day, that is enough water to supply the needs of nearly 22 million people each year,” calculated Jay Famiglietti, director of the University of California Center for Hydrologic Modeling.

Famiglietti has been tracking groundwater levels since 2002 using satellite technology. He shared his dire findings during a daylong groundwater workshop with the State Board of Food and Agriculture.

“We’re mining groundwater, meaning we’re using it faster than it’s being replaced,” Famiglietti explained. He said the problem is in the San Joaquin Valley – not the Sacramento Valley – and it has been getting worse since 2006.

“People need to truly understand groundwater is disappearing,” Famiglietti stressed. “Without intervening, that water is not coming back.”

He is part of a growing cadre of hydrologists and scientists calling for more government control over how much water gets pumped out of the ground. State lawmakers not only are listening to their pleas, but also have started drafting plans for how the government can protect California’s water basins.

That’s new, because California currently has very few restrictions on groundwater pumping and only sketchy data on how much water is being sucked out, and by whom.

A sinking feeling

“People are having to drill deeper and deeper wells to chase the water lower and lower,” said Eric Oppenheimer from the State Water Resources Control Board’s office of research and planning.

That’s serious because more than 30 percent of California’s water for agriculture and urban use is pulled from the ground, Oppenheimer said. Reliance on groundwater increases to 40percent during dry years when surface water supplies shrink.

California doesn’t have a statewide groundwater management system, but something like that may be coming soon. “We think local and regional management is the most effective way to protect groundwater,” said Oppenheimer. He said state officials are considering “surgical, focused” oversight of water use in regions “where ongoing management and control efforts are not protecting groundwater.”

That is why the state water board last month released a 10-page Groundwater Workplan Concept Paper outlining the issue and the options for new regulations. That plan notes how the government could “take enforcement actions of varying types and levels of stringency” to protect groundwater.

“We envision a future where well-equipped local and regional groundwater management entities use monitoring information and thresholds to manage and maintain groundwater of sufficient quality at sustainable levels over the long term; and where local and regional management efforts are backed up by state support and oversight, where needed,” the concept paper states.

Establishing protective groundwater thresholds is important, the report contends, because “quantifiable triggers” are needed to signal when corrective actions must be taken.

Rules and fees considered

The report argues that physical differences in California’s groundwater basins “do not lend themselves to a ‘one size fits all’ solution” to the overdraft problem. But enacting legislation to manage groundwater withdrawal, use, storage, monitoring and reporting is among the proposals. Fees to cover the costs of monitoring and managing groundwater also are being considered.

The presentations last week to the Board of Food and Agriculture point to an urgency to act sooner rather than later. “We don’t know how much groundwater is pumped in California,” said Steven Phillips, a hydrologist with the U.S. Geological Survey. But he said declining groundwater levels are causing significant portions of the Valley’s surface to sink. In some overpumped portions of the state, Phillips said, the land above those basins has sunk 30 feet since the 1930s.

“The global poster child for subsidence is the San Joaquin Valley,” explained Phillips, noting that there is an 80-mile-wide region south of Merced where ground levels have fallen as much as two feet in two years. That’s bad because once underground water basins collapse, they never can refill with water.

“The big challenge is to get more water into the groundwater systems,” Phillips said. He is working on a geographic solution to that problem in Stanislaus County, where he’s been creating a 3-D computerized mapping system to identify places where the aquifer can be recharged most easily. By flooding fields that have the right soils, Phillips said, water can drain down to help refill underground basins for future use.

He said some California communities even have had success using recycled water to recharge groundwater basins.

Call for regulations

Whatever the solution, protecting California’s groundwater is critical, insisted Ruth Langridge, a professor at the University of California, Santa Cruz, who is researching groundwater reserves. “Enforceable standards for groundwater withdrawals” are needed to secure water supplies for the future. Although there currently are few restrictions on pumping, she said, “cities and counties have an ability to pass ordinances to manage their groundwater.”

The Stanislaus County Board of Supervisors last month approved a modest measure to protect groundwater. Starting Dec. 17, the county will restrict out-of-county transfer of groundwater or pumping to replace surface water sold to buyers outside the county, but the ordinance includes numerous exemptions.

Many Stanislaus residents don’t think that ordinance will do enough. The Turlock City Council last month voted to ask county supervisors to consider a moratorium on drilling for new agricultural production wells. Its main concern stems from the rapid conversion of rangeland in eastern Stanislaus County to orchards and vineyards.

To water those new permanent crops, an unprecedented number of industrial-size wells have been drilled. Those new wells, combined with two years of relative drought, are believed to be at least partly responsible for some older wells going dry around Denair.

Stanislaus County officials say they’re continuing to study options for protecting groundwater reserves.

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