Technology Use Up, Water Use Up

Those who advocate high-efficiency irrigation techniques claim win-win-win solutions -- less water used, more production, lower costs -- but their claims are mainly based on theory and spreadsheet simulations. (For example, see this post on the Pacific Institute's latest report favoring technology to conserve water.)

Unfortunately, there's another possibility -- that farmers may install high-efficiency systems BUT use MORE water. (We already know of this outcome when farmers switch from flood to drip irrigation. There's less runoff/ground water recharge, but plants use more water.)

Thus, we need some empirical evidence to help us understand which outcome is more likely to happen. Conveniently, some researchers at my old department at UC Davis have looked into this question, and this [PDF] is what they find:

We consider two voluntary, incentive-based groundwater conservation programs and estimate their effects on groundwater extraction for irrigated agriculture. We find that the programs do not have the intended effect; the subsidization of more efficient irrigation technology induces the production of more water-intensive crops, thus increasing total extraction, and land retirement programs are generally not utilized on irrigated land, thus having little effect on groundwater extraction.

So the Pacific Institute's proposal to subsidize the use of technology to reduce agricultural water use is more likely to increase use than decrease it.

What would decrease water use? Higher prices for water use and the opportunity to sell water that's conserved.

Bottom Line: Farmers want to make profits. If you lower their cost of water, they will use more. If you want them to use less, make it more expensive to use or more profitable to sell!