Agricultural Water Efficiency May Do More Harm Than Good

Using water more efficiently in farming may ultimately increase long-term water shortages, warn some water experts. Although efficiency efforts — such as lining irrigation ditches to prevent leaks and delivering water directly to roots rather than flooding fields — are touted as a solution to problems ranging from food shortages to dry rivers to international water disputes, the notion that water is “saved” rests on the mistaken assumption that it is ever “wasted,” argues Stephen Foster of the British Geological Survey. Water used inefficiently by farmers seeps down to replenish underground water reservoirs, he says, and it’s from these same reservoirs that farmers pump water to supplement river flows for irrigation. Using this “leftover” water elsewhere could eventually deplete underwater reservoirs, leading to more severe long-term shortages. Of course, enviros might argue, among other things, that using more water for agriculture means more water will get polluted with agricultural chemicals.