Abstract
Estimating groundwater recharge rate is essential for water sustainability of the arid region of the United Arab Emirates that receives most groundwater recharge from the bordering mountain ranges in Oman. Analyses of major ions, stable isotopes (delta H-2 and delta O-18) and the radioactive isotope (C-14) and the HydroGeoSphere (HGS) three-dimensional numerical model approach were applied here to investigate groundwater residence time in the aquifers and the recharge rates in the region. Estimate of groundwater recharge ranges from 1.03 to 36.6 mm/year with an average of 5.8 mm/year based on groundwater ages and ranges from 0.23 to 35.3 mm/year with an average of 6.5 mm/year based on HGS modelling. The data provide vital information for making sustainable plans for natural water resources with expected future reduction in rainfall in this region and other arid areas of the Middle East and the world.