In present study, physical based Water and Energy Budget – based Distributed Hydrological Model (WEB-DHM) was applied to investigate the intra-basin river runoff and to elucidate the potential impacts of climate change on hydrology in the Soan River Basin, Pakistan, a semi-arid and poorly gauged basin (PGB). The model performance was evaluated in terms of river discharge and soil moisture. WEB-DHM simulated surface soil moisture was validated by soil moisture assimilated by Land Data Assimilation System developed by the University of Tokyo (LDAS-UT). WEB-DHM was derived with bias corrected precipitation and other parameters from four Atmosphere-Ocean General Circulation Models (AOGCMs). The analysis of twenty years simulated daily discharge for the past (1981-2000) and future (2046-2065) showed that it is likely that flooding trend will increase in the future. However, it is about as likely as not that the drought will intensify in the future. The study demonstrate an example for climate change impact assesnhydrological processes in a PGB.