Conclusion:
This study presented a method that integrated future climate and land use projection with a hydrologic model to investigate the water balance under combined effect of climate change and land use change. To address some level of the uncertainty with the approach we used three CMIP5 GCM outputs under two emission scenarios (RCP4.5 and RCP6.0). the future time period was split in two time period (mid-century and late-century). Calibration and sensitivity analyses were carried out to make sure the hydrologic model output is reliable. Results show increase in temperature and precipitation in UCS. Annual maximum and minimum temperature are projected to increase up to 30% especially during Summer and Winter. Rainfall will also increase by around 11%, however different emission scenarios showed different trend through the simulation period. surface runoff, water yield, and discharge at the two stations were estimated to increase. However, surface runoff changes were the largest. Increases in discharge during Summer and Fall are more extreme than other seasons. ET has the modest changes and is expected to decrease. This study can be helpful as an example for areas that mainly comprised of forest and agricultural cover. Additionally, this study can provide information for investigating how future climate data and land use projections could impact hydrological processes. In Southeastern watersheds. This region has not been under focus for climate and land use management studies. Moreover, data and results shown here can provide help in sustainable management especially for Native American Reservations located within Upper Choctawhatchee subbasin. The model used here, showed satisfactory performance that can be further used to study best management practices, water quality modelling (NPS and PS pollution) and also to track extreme weather footprint such as hurricane and tropical storms, and droughts which have been more frequent recently.