Climate Change Impacts on Nutrient and Sediment Loads in a Midwestern Agricultural Watershed

Abstract

The objective of this study is to examine the water quality impacts of climate change in a predominantly agricultural, but rapidly urbanizing, watershed in the American Midwest, the Little Miami River (LMR) watershed. Future climatic conditions were simulated based on various climatic scenarios. The Soil and Water Assessment Tool (SWAT), a long-term, continuous, watershed-scale hydrologic model, was used to predict the potential changes in flow, total nitrogen, total phosphorus, and sediment loads. Results indicate that daily flow can vary by 35%. Besides, the LMR watershed has an overabundance of phosphorus. It is likely that eutrophication will be exacerbated in future climatic conditions; hence strategies to control non-point source pollution by only reducing nitrogen may not be adequate. Moreover, the hydrological impacts of future climate change will be large enough to warrant modifications in our response and utilization of water resources.