Cold Water, Hot Debate: Does California Agriculture Use 40% or 80% of the State’s Freshwater?

Here’s how the percentages are calculated, so you can decide for yourself.

By Jenny Bryant

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Bordering a fallow field in California’s Central Valley, an irrigation ditch carries water destined for other uses.

Just how much of California’s available freshwater is used for agriculture? This amount is often reported at 80%, with the remaining 20% allocated for urban use. (A third division of usage—industrial—is typically included in the “urban” and “agricultural” categories.) However, the key word here is “available.”

To reach the percentages above, only water that’s available or “developed” for economic uses is taken into account. When environmental needs for freshwater are entered into the equation, the breakdown is roughly 50% environmental, 40% agricultural and 10% urban, this according to numbers reported by the Public Policy Institute of California.

Yet, even the latter numbers—those accounting for environmental usage—are contested. Splitting the difference, UC Davis’s Center for Watershed Sciences argues that while many environmental uses should be included in the state’s total water budget, wild and scenic rivers should not, because it is not possible for them to provide water for human use. This reconfiguration renders state freshwater usage as 62% agricultural, 22% environmental and 16% urban.

Need another opinion? Blaine Hanson of UC Davis offers one that considers the variance in precipitation: only 52% of California’s total water supply (not just that developed for economic uses) is used by agriculture in a dry year, and only 29% is used in a wet year.

<< See the full story, “Not Just a California Problem.”

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