Impact of climatic changes on surface water in Middle East, Northern Iraq

The climate changes affect the hydrological cycle and the flow systems of waterways, which in turn alter the volume of water available resources locally, regionally, and globally at various levels. This study aims to evaluate the impact of the climatic changes on the availability of surface water resources in the basins of the Tigris, Great Zab, and Khazir Rivers in Iraq by applying the general circulation model HadCM3 under two climate change scenarios (SRES-A2 and SRES-B2). According to the analysis findings, the annual rainfall will be reduced in the future under scenario (A2, B2-2030) by 2.67% and continue reducing under scenario (A2, B2-2060) by 5.35%. The decrease in rainfall will reduce surface water runoff within the drainage basin by 2.64% under scenario (A2, B2-2030) and 5.45% under scenario (A2, B2-2060). The obtained results reveal that the decrease in rainfall was countered by an increase in temperature, as well as by an increase in evapotranspiration. The average correlation coefficient of rainfall with temperature and evapotranspiration is - 0.93, whereas the rate of correlation coefficient with relative humidity and surface water runoff is 0.96. All scenarios and predictions indicate that the study area will be on the verge of a drought period in the not-too-distant future, so the study recommends urgently the ministry of water resources in Iraq to manage properly the waters of the three rivers by building dams on their channels and storing water in the wet seasons for the benefit of the dry seasons.