Projected changes in monthly baseflow across the U.S. Midwest

Abstract:

Understanding future changes in baseflow is a major concern for water supply and ecosystem health because it is what sustains streamflow during periods of drought. This study examines the impacts of climate and agriculture on monthly baseflow in the U.S. Midwest through the end of the 21^st century. We use a statistical approach to evaluate different future climatic and agricultural scenarios. The results are based on downscaled and bias corrected Global Climate Model (GCM) outputs and the Representative Concentration Pathway (RCP) 8.5. In terms of agricultural changes, we consider three scenarios representative of increases, decreases and status-quo with respect to the production of corn and soybeans. The combination of climate change and present-day agricultural conditions suggests increases in baseflow are likely a result of increased precipitation and antecedent wetness. Increases (decreases) in agricultural intensity are found to amplify (mitigate) the impact of climate. More specifically, expanding corn and soybeans is projected to lead to increasing trends in baseflow from June to August in the Corn Belt region. On the other hand, converting land back to perennial vegetation would decrease baseflow throughout the entire year. Despite its simplicity, this study can be used to understand where to expect adverse effects on baseflow and improve land management practices in those areas.