Declining Soil Moisture Threatens Water Availability in the U.S. Great Plains

Abstract

HighlightsFuture water security in the U.S. Great Plains is threated by a drying trend in average annual soil moisture.Agricultural management will become increasingly challenging due to declines in surface water storage.Alternative management strategies are needed to meet future environmental and anthropogenic surface water demand.Abstract. Spatiotemporal trends in soil moisture are of considerable importance within the food-energy-water nexus. Soil moisture dictates the productivity of ecosystems, plays a major role in land-atmosphere interactions, influences climate change projections, and shapes future water security. Monitoring of long-term soil moisture trends has proven useful for managing water resource allocation and developing solutions to global water security challenges. Thus, we examine annual trends in surface soil moisture throughout the U.S. Great Plains region from 1987 to 2016 using data from NASA’s observation-driven SPoRT-LIS land surface model at 3 km resolution. Results reveal a drying trend in soil moisture for a majority of the U.S. Great Plains, although wetter conditions have been realized in the northernmost region of the Missouri River basin. These results, when coupled with climate change-driven increases in temperature and evapotranspiration, will inevitably drive baseline soil moisture to drier conditions in the future. Under drying soil moisture conditions, future agricultural production and water resource management in the U.S. Great Plains will become increasingly complicated, thereby threatening future food and water security. However, these results can be applied to inform and improve climate change adaptation strategies in order to ensure adequate volumes of freshwater to meet future human and environmental water demand. Keywords: Climate change, SPoRT-LIS, Trend analysis, Water security.