The implemented HEC-HMS model was superior in modeling the streamflow data.  annual river runoff will likely decrease under all scenarios of RCPs and time stages of the future period.  CFSR weather data has been successfully used to model the Khabour basin.In arid and semi-arid areas, assessing the potential impact of climate change on water availability is of critical importance for achieving better management of future water resources. Iraq as one example of those areas is expected to experience more stress on water due to the climatological characteristics and to the rapid population growth in addition to the policy of the riparian upstream countries. Therefore, the present study aims to quantify the impacts of climate change on the Khabour River catchment north of Iraq, which is one of the riparian catchments between Iraq and Turkey. The HEC-HMS model was firstly calibrated and validated against daily streamflow data measured for the period 01Jan2004-30Jun2009 near the catchment outlet at Zakho station. Thereafter, the future climate changes data from the HadGEM2_ES model was fed into the calibrated HEC-HMS model to quantify the future water resources availability.The impacts of climate change on the water under four possible scenarios of RCPs (RCP2.6, RCP4.5, RCP6, and RCP8.5) of atmospheric greenhouse gas (GHG) concentrations for three future slice periods (2021-2030), (2041-2050), and (2061-2070); was assessed in attribution to that from the period (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009).Results show that the implemented HEC-HMS model was superior in modeling the streamflow data. NSE, R² and RMSE value was 0.871, 0.89 and 26.7, respectively, for calibration and 0.936, 0.9364 and 18.0, respectively for validation. The results also suggest that annual river runoff will likely decrease under all scenarios of RCPs and time stages of the future period.