With drought gripping California, there’s a renewed push for spending on ag water conservation measures. Brett Walton explains why not every gallon saved is really a gallon saved:

“Farmers are several times smarter than politicians, and they have done a good job convincing the government to help pay for more efficient irrigation systems. Politicians actually believe that these more efficient systems will make the water last for their children and grandchildren,” Bob Stewart, an agriculture professor at West Texas A&M University, told Circle of Blue. “The fact is that a more efficient system in many cases uses more water, not less.”

Irrigation efficiency is a ratio. It measures how much of the water put on a field is used by the crop compared to how much soaks into the ground and does not aid plant growth. Higher efficiency leads to higher yields, which increases water consumption because extra water is needed to nourish a larger plant. Even though a farmer might draw the same amount of water from a river or an aquifer, he returns less to the source if he is more efficient.

The unintended consequences of irrigation efficiency, well-established by years of scientific study but often ignored or misunderstood by policymakers, holds special relevance today as many of America’s top farming regions cope with devastating droughts.

The entire article is very much worth reading.