481 - Effect of Aquifer Geometry and Land Topography on Seawater Intrusion under the Conditions of Climate Change

Groundwater resources represent the main source of freshwater in many costal aquifers around the globe and specifically in arid and semi-arid regions. In the meantime, seawater intrusion in coastal aquifers constitutes a global problem that affects the quality of the groundwater and hinders the proper exploration of such aquifers. The degree of the intrusion depends on many natural and manmade parameters. Natural parameters include the physical setting of the aquifer such as the aquifer geometry and land topography as well as geological and hydrogeological parameters and rainfall and natural recharge events. Manmade parameters include pumping and artificial recharge, irrigations practices and others. The expected seawater level rise under the conditions of climate change represents another important parameter. This study focuses on the effect of aquifer geometry and specifically the depth of the aquifer at the seaside, the land topography, and seawater level rise on seawater intrusion problems. To that end, two costal aquifers of different scales, geometry and settings are considered, including the Nile Delta aquifer in Egypt and the Wadi Ham aquifer in United Arab Emirates. The Nile Delta aquifer is among the largest reservoirs in the world and with a depth of around 1000 m at the seaside. The Wadi Ham aquifer is a relatively small aquifer with a depth of around 30 m at the seaside. In addition, the land surface of the Nile Delta aquifer is of low altitude, while the land surface in the Wadi Ham is of higher altitude. FeFlow is used to simulate the seawater intrusion in the two aquifers. It is concluded that both the aquifer depth at the seaside and land topography have the major impact of the degree of the seawater intrusion under the conditions of climate change.