California begins to recognize need for groundwater monitoring

By on Fri, May 15, 2009

The ground subsided 50 ft between 1925 and 1977 in areas of the Central Valley due to groundwater pumping.

California at minimum should monitor and probably should regulate groundwater use, according critics quoted in the New York Times.

Since 2006 the surface of the aquifer, in the Kaweah subbasin of the San Joaquin basin, has dropped 50 feet as farmers pumped deeper, Mr. Watte says. Some of his pumps no longer reach far enough to bring any water to the surface. ...

Recent scientific studies indicate that in the long term, climate change is diminishing the potential for the Sierra snowpack to generate enough runoff. Aquifers are thus a crucial insurance policy for water users.

Critics argue that refusing to monitor and regulate groundwater could prove catastrophic to the state’s real estate sector and its $36 billion agricultural economy. ...

But even Mr. Schwarzenegger is heeding the growing drumbeat on groundwater. Issuing an emergency drought declaration in February, he asked local governments and water districts for the first time to supply the state with data on groundwater supplies.

Compliance so far has been spotty, said Mark Cowin, deputy director of the state’s Department of Water Resources. "In a lot of cases," Mr. Cowin said, "it’s simply a matter of the information not existing."

On the grass-roots level, resistance to monitoring is based not just in a property-rights credo but also in a belief that the state can ride out any dry spell. ...

Don Mills, general manager of the neighboring Kings County district, sees only two solutions: recharging aquifers by creating asphalt- and agriculture-free zones where water can be pooled to percolate down to the aquifer, or pumping less.

San Mateo County’s recently-released groundwater study was unable to draw firm conclusions about the security of the Coastside’s groundwater supply because of inadequate data collection by the county. From the study:

However, as the study progressed, it was determined that safe yield and groundwater/habitat relationships could not be accurately assessed due to the limited availability of well data, concerns regarding the accuracy of the data, and information gaps regarding surface water flows.