The effect of climate change on groundwater recharge in unconfined aquifers in the western desert of Iraq

Abstract

Iraq is located in a water-stressed area with little of its own water resources. This means that groundwater is one of the main water resources for this region, this true for other countries in the Middle East. The impact of global warming and climate change in the future, through increases in temperature and fluctuations in rainfall, will escalate water scarcity and the degradation of the quality of water across different water resources. In the current study, the impact of future global warming and climate change on groundwater natural recharge in an unconfined aquifer (Umm Er Radhuma), in the Western Desert of Iraq, was assessed using the simulation tool WetSpass. Future climatic parameters pertaining to the study area, were predicted by downscaling a General Circulation Model (GCM), the second Canadian Earth System Model (CanESM2). CanESM2 was applied to two expected emission representative concentration pathway scenarios; medium RCP4.5 and high RCP8.5, across a period spanning 2020 to 2099, in seven meteorological stations distributed throughout the study region. Based on the statistical indicators from the validation process, the downscaling modeling operation was deemed efficient at predicting climate parameters (average temperature, precipitation and wind speed) during the chosen period. The calibrated future simulations scenarios projected that precipitation will decrease by 9.2% and 14.1% for RCP4.5 and RCP8.5 emissions scenarios, respectively. The temperature will increase by 0.96 °C under RCP4.5 and 2.05 °C for RCP8.5. Annual groundwater recharge is predicted to decrease by 13.6% and 21.2%, under RCP4.5 and RCP8.5 emissions scenarios respectively, by the end of the present century.