Assessing impacts of bioenergy crops and climate change on hydrometeorology in the Yazoo River Basin, Mississippi

The objective of this study was to assess the impacts of bioenergy crop production, such as switchgrass (Panicum virgatum L.) and miscanthus (Miscanthus×giganteus), and climate change on hydrometeorology. The soil and water assessment tool (SWAT) model was used to simulate hydrometeorological consequences and crop yields in the Yazoo River Basin (YRB) in northwestern Mississippi. Modeling results of streamflow and soybean and corn yields during the calibration and validation periods were consistent with the observed data. The yields of bioenergy crops were predicted using the calibrated SWAT model. In order to generate future climate change data, the Geophysical Fluid Dynamics Lab (GFDL) CM2.1 global coupled climate model was selected as a general circulation model (GCM). The output of the GFDL CM2.1 with the Special Report on Emissions Scenarios (SRES) A1B emission was downscaled by LARS-WG stochastic weather generator. Eight scenarios including bioenergy crop production and climate change were evaluated using the SWAT model. The results of this study indicate that the bioenergy crops will increase annual evapotranspiration and decrease annual surface water, water yield and streamflow. Furthermore, the future climate change scenarios showed that the increase in atmospheric carbon dioxide (CO2) concentrations will decrease annual evapotranspiration, which eventually will lead to an increase in annual surface runoff, water yield, and streamflow. However, decreased precipitation in the future periods will be the dominant cause of a decrease in annual evapotranspiration, surface runoff, water yield, and streamflow. Comparison of all scenarios showed that climate change is likely to affect hydrometeorology more significantly than bioenergy crop production, and the scenarios of the conversion of soybean and corn to miscanthus are more significant than the switchgrass scenarios. This study will help to develop future watershed management programs related to bioenergy crop production and climate change conditions within the Yazoo River Basin, which may also be applied in other geographic areas in the country and abroad.