Satellite-Based Estimates of Groundwater Storage Changes at the Najd Aquifers in Oman

The Najd aquifers in Oman, are located in one of the most arid zones in the world. In such regions, there is a shortage in the water resources where groundwater is a very critical component for human life. The main aim of this contribution is to use the satellite remote sensing data of the Gravity Recovery and Climate Experiment (GRACE) along with the Global Land Data Assimilation System (GLDAS), to estimate the groundwater storage changes at the Najd aquifers. Groundwater storage changes were calculated from both GRACE/GLDAS data and from the groundwater level measurements. It was found that the estimated groundwater storage changes from GRACE and water levels coincide in their trends showing a noticeable depletion within the time period from Oct. 2002 to Sept. 2014. The spatial distribution maps of the groundwater storage changes show slightly changes from Oct. 2003 to Sept. 2010, but a significant decreasing were observed from 2010 to 2014. The groundwater storage over Najd aquifers was decreased by about 0.44 and 0.46 km(3)/year as calculated from GRACE data and groundwater levels, respectively. We also found that groundwater storage was affected by the strong storm events as observed in 2007 and 2010. This contribution could be helpful for the long term sustainable groundwater management in the study area and other arid regions.