Over the last couple of years, I’ve come across several examples of how increased agricultural irrigation efficiency hasn’t led to water savings. When interviewing a farmer in San Joaquin County about managing agricultural pumping loads, he described how he had invested $2,000/acre in a microdrip system for his tomato and melon fields. To avoid his subterranean systems, his farm has a GPS repeater that guides his tractors within a few inches. Another consultant described how they couldn’t find any flood irrigated tomato fields, a standard method in 2007, for a comparison survey for drip effectiveness. Fresno County tomato yields increased more than 25% from 2007 to 2012, and individual field yields have increased 50%.
The result is that growers are using the water they have to increase productivity. They also have moved into more permanent crops which deliver higher revenues per acre-foot. For example, almond acreage has more than doubled since 1995. And little additional water has been freed up for urban or environmental uses.
With the increased value of water to agriculture, urban agencies have lost much of their competitive edge in pursuing water transfers. In 2014, Westlands Water District paid Placer County Water Agency an unheard of $325/AF, and there were reports of some transfers costing several thousand dollars per AF to protect orchard investments. The urban agencies use to largely have this playing field to themselves, but that era looks to be ending.