A coupled model simulation assessment of shallow water-table rise in a Saudi Arabian coastal city

•The study aim was to investigate the cause of a rising shallow water table in Dammam city, eastern Saudi Arabia.•This study was conducted by combining geophysical and hydrogeological investigations with numerical modelling.•A coupled HYDRUS-MODFLOW modelling package was applied to simulate the vadose and saturated zones.•Leakages from underground pipe network systems were found to be the principal contributors to the shallow water-table rise problem.

The problem of a rising shallow water-table level in the coastal city of Dammam in eastern Saudi Arabia was investigated through data collection, analysis, and numerical modelling. The research focused on applying a coupled model that considers flow in both the saturated and unsaturated zones. Geophysical and hydrogeological data were collected through field investigations, and various analyses of this data were performed. A computer simulation model of shallow groundwater flow was developed and applied to define the recharge sources. The generalised HYDRUS and MODFLOW modelling packages were coupled to simulate the vadose zone and saturated zone, respectively. The calibrated coupled groundwater model was used to determine the contributions of each possible recharge source, and thus to identify the major causes of the rise in the water table. The shallow water-table rise was found to be a serious threat to the present and future development of this large city.