Abstract: | This study quantified the impacts of climate change on water availability over the Flint River subwatershed (FRW) located in the
Wheeler Lake Watershed (WLW) in northern Alabama. The observed climate data were obtained from the Alabama Mesonet Stations, and the
modeled climate was obtained from multiple models, multiple scenarios, and multiple projections available through the World Climate
Research Program’s database. The hydrologic model, the soil and water assessment tool (SWAT), was calibrated and validated for the period
of 2004 to 2013, based on daily meteorological forcing and monthly streamflow data. Various climate scenarios developed with respect to
anticipated future climate until 2100, based on representative concentration pathways (RCPs), were forced into the calibrated SWAT model
to quantify future water availability. The simulated average change in monthly streamflow varied from þ23 to −46%, þ29 to −48%, þ40 to
−48%, and þ38 to −48% for scenarios RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5, respectively; the simulated total annual streamflow varied
from þ18 to −28% for the same scenarios. However, average change in total annual streamflow based on all scenarios showed a decreasing
streamflow pattern from −0.3 to −1.2% for future periods, except a slight increase of þ0.17% at the end of this century. The simulated results
that quantified water availability under changing future climate conditions can be used by water managers, stakeholders, and decision makers
in planning and managing available water resources and their allocations based on users and water demands, and in considering alternatives
for monitoring and mitigating long-term impacts |