This floating armor against evaporation can reduce water loss by 90 percent
Scientists predict water stress in the West will increase dramatically in the coming decades, as climate change increase evaporation rates, shifts rainfall patterns, and impacts snowpacks in complex ways.
A 2019 study in the transdiciplinary journal Earth’s Future pointed out that the Central Rocky Mountains, Great Basin, Southwest and California are all likely to face extreme water scarcity in the 21st century, given population and climate change models. More worryingly, it noted that a continuation of the decades-long trend of reductions in per‐capita water withdrawal rates, “are essential but insufficient to avoid impending shortages.” Instream flow reduction and ag-to-urban water transfers will become increasingly necessary to satisfy demand.
With that in mind, it is particularly critical for land stewards in the West to maximize water use efficiency in their operations. And an innovation that shows promise for livestock producers in particular are “shade balls,” which are also highlighted briefly in “Slaying salt cedar to save New Mexico’s eastern plains” (p. 62). Shade balls, black plastic spheres that float on top of livestock water tanks, lower evaporation dramatically, keep birds from spoiling water with excessive droppings, prevent algae and moss growth, and reduce freezing, but are gently nudged out of the way by thirsty cow noses.
Tuda Crews of Ute Creek Cattle Company, where shade balls have been deployed since 2016, reports that by covering the surface of a 20 ft. tank with shade balls, evaporative loss drops 90 percent: every 20’ tank covered with the balls saves 16,000 gallons of underground water each year.
Photo: Tuda Libby Crews (left) describes to a visiting videographer how Ute Creek Cattle Company employs shade balls to reduce evaporative losses in their stock tanks.