Long-term Saltwater Intrusion Modelling – Case Studies from North Africa, Mexico and Halle

Coastal saltwater intrusions threaten drinking and irrigation water resources along coastlines. On the other hand submarine groundwater discharges in nearly the same areas. The interface between saltwater and freshwater shifts over time and is mainly influenced by the seawater level and aquifer characteristics. During the last 140,000 years, seawater level fluctuation was very rapid. After a fast rising of about 120 m in the last interglacial, a slow drawdown of the same magnitude followed during the last glacial within 100,000 years. In the last 10,000 years, the water level again rose very fast and then it remained stable. Different aquifer types are influenced by these fluctuations in different ways. The two examples from North Africa and Mexico show how not only shelf platforms are flooded but also the interface in the ground water shifts over time. Both investigation areas are transboundary aquifers and the water supply of the population is affected directly by the hydrogeological development.