Quantification of Modeled Streamflow under Climate Change over the Flint River Watershed in Northern Alabama

Abstract:

This study is carried out to quantify the impacts of climate change and land use change on water availability over the Flint River watershed (FRW) located in the wheeler lake watershed in Northern Alabama. The FRW directly drains into the Tennessee River, which is a major source of water supply for the Southern States. The observed precipitation and temperature data are obtained from the Alabama Mesonet Stations which are also a part of National Resources Conservation Service (USDA NRCS) Soil Climate Analysis Network (SCAN). The GCM simulated climate data are obtained from the WCRP CMIP5 ensemble that consists of 234 downscaled climate projections from four emission scenarios and 37 GCMs. The hydrologic model SWAT is calibrated and validated for a period of 2004 to 2014, based on daily meteorological forcing and monthly streamflow data for the FRW. A total of 15 parameters that directly influences the surface/base flow and basin response are selected and calibrated. The anticipated change in future climate (2030s, 2050s, 2070s, 2090s) with respect to baseline period (2004-2014/2010s) for each emission scenario are introduced into baseline climate to perturb it to future climate pattern. Various climate scenarios based on future climate are forced into the calibrated SWAT model to quantify future water availability over the basin and compared with the baseline period. This is a part of the Geospatial Education and Research Center (GERC) project and the major research findings from this project will help decision makers in evaluating the combined impacts of climate change and land use change on water availability, and developing strategies to sustain available natural resources.