Abstract
Gravity Recovery and Climate Experiment (GRACE) data, along with readily available remote sensing datasets and the outputs of land-surface and climate models, are used to monitor spatiotemporal variabilities in the groundwater resources of the Red Sea Coastal Aquifer (RSCA) system in Saudi Arabia; to investigate their responses to climate projections; and to provide sustainable and resilient management scenarios for these resources. Our results indicate that, during the investigated period (April 2002–June 2017), the RSCA received an average annual recharge of 3.16 ± 0.52 km3. Recharge events (~16% of rainfall) are related to the observed increase in rainfall rates. Analysis of climate models' outputs over the RSCA indicates an increase in the median annual rainfall (17–31%) and recharge rates (2.7–4.9%) by the end of the 21st century. To ensure sustainable management and utilization of RSCA's water resources, groundwater extraction should be located in the southern and central parts of the aquifer, and groundwater extraction rates should be kept lower than 2.0 km3/yr. Findings highlight the importance of GRACE data as a unique, cost-effective, and decisive tool in monitoring the health of coastal and inland aquifer systems across the globe.
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•Red Sea Coastal Aquifer (RSCA) system in Saudi Arabia is receiving modern recharge.•Annual recharge rates (3.16 ± 0.52 km3) are estimated at 16% of rainfall rates.•Annual rainfall and recharge rates are projected to increase over the RSCA.•Groundwater extraction should be located in the southern and central parts of RSCA.•GRACE provides a cost-effective tool to monitor health of coastal aquifer systems.