Rethinking California's Irrigation Strategy

"California is in a "state of drought," something Gov. Arnold Schwarzenegger made official in June when he issued directives calling for "immediate action" on conservation and enhanced supply. (About half of the state's developed water supply is used directly by people; the balance goes for environmental uses like maintaining wild rivers or endangered species.)

Beyond California's history of periodic drought, Heather Cooley, of the environmental advocacy-oriented Pacific Institute, said climate change predictions forecast "more severe" and "more frequent" dry spells.

She added that farmers are facing increasing competition for water from expanding cities and industries — and declining species.

A 2007 court ruling restricts pumping on the delta to protect an endangered fish species, the 2-inch-long delta smelt, once the most common fish in the delta but now in such dire shape that the accidental killing in the pumping plans could extinguish the species.

For all of these reasons, Mike Wade, executive director of California Farm Water Coalition, said many Central Valley farmers expect to see their water allocations for the current growing season reduced 30 percent or more. Some have decided to cut their losses and let their fields go fallow."