Reducing irrigation of livestock feed is essential to saving Great Salt Lake

Abstract

The Great Salt Lake of Utah (US) is of great economic, cultural, and spiritual importance, yet rapid depletion of the lake in recent decades gravely threatens these values. The lake's shrinkage is attributable to anthropogenic consumption of 62% of river water that would have otherwise reached and replenished the lake. The lake's water balance has been in deficit for much of the past century, but during recent decades climate warming and drought has reduced basin runoff, while anthropogenic water consumption has not been reduced to a commensurate degree, driving the lake's water budget further into deficit condition and causing an average lake level decline of 0.1 meter/year during 1989−2022. Agriculture accounts for 71% of anthropogenic depletions, with 80% of agricultural water going to cattle-feed crops (alfalfa and grass hay) to support ∼980,000 head of cattle for dairy and beef production. We propose a target goal of reducing total anthropogenic consumption by 35% to stabilize and begin refilling the lake, and explore potential policy solutions for attaining this conservation goal. We find that the most potent solutions would involve a 61% reduction in alfalfa production along with fallowing of 26–55% of grass hay production, resulting in reductions of agricultural revenues of US$97 million per year, or 0.04% of the state's GDP. Farmers and ranchers involved in cattle-feed production, along with related agricultural businesses, could be fully compensated for lost revenue generation at a cost ranging from US$29-$124 per Utah resident each year, depending upon which water conservation strategies are deployed. Dairies dependent upon alfalfa produced in the Great Salt Lake basin would need to increase imports of these crops from other river basins to sustain production at current levels. This case study of a water-stressed basin with dominant agricultural water use illustrates globally transferable approaches for rebalancing the water budget of stressed water basins by reducing consumptive water use on irrigated farms. The approaches described here require detailed accounting of water consumed by individual crop types.