University of California Cooperative Extension irrigation specialist Lawrence Schwankl joined with irrigation scientists from Cal Poly San Luis Obispo and Fresno State University in writing a rebuttal to a September 2008 report by the Pacific Institute titled "More with Less: Agricultural Water Conservation and Efficiency in California—A Special Focus on the Delta."
The university scientists' commentary was published in part yesterday in AgAlert and the full, 13-page PDF version is available from the California Water Institute Web page.
In AgAlert's summary, the authors wrote that, "The Pacific Institute paper directly draws incorrect conclusions, or infers incorrect conclusions, based on significant errors in its underlying assumptions."
They said the Pacific Institute asserted their report fills an important gap.
"This report is not a comprehensive analysis of agricultural water use and it fills no gap. As a means of prompting more discussion it only states the obvious," the commentary's authors wrote.
The commentary goes on to point out what it calls "fatal flaws" in the Pacific Institute's report.
"The (Pacific Institute's) conclusions assume that on-farm water savings can be directly translated into equivalent basin-wide savings. Such an assumption is incorrect," the scientists wrote. "You simply cannot apply an estimate of on-farm water savings to an entire basin to estimate net transferable water conservation. We note that the Pacific Institute paper implicitly agrees with this argument, but then goes on to ignore the basin-wide concept completely."