Flash floods along the Red Sea coast are getting more and more into consideration as with rising population and tourists, and the damages caused by flash floods are stronger impacting the life in this region. Investigations in El Gouna close to Hurghada concentrate on a basic description of the basin, geological features, and climate conditions and in the second place on modeling rainfall-runoff during storm events close to the city. The Wadi Bili catchment, which is connected to the coastal plain of El Gouna, is morphologically and geologically structured into the high mountains of the Red Sea Hills, the Abu Shar Plateau between the high mountains and the steep slope of Esh El Mellaha which separates the coastal plain from the upper parts of the catchment. 3D geological modeling of the plain on the basis of stratigraphic correlation separated three different aquifers where the uppermost is of interest for abstraction of groundwater for desalination. Porosities are about 0.2 and provide good conditions for artificial recharge, even the drainable porosity is much lower. A hydrodynamic flash flood model for the region of El Gouna is presented to simulate the spreading of water and flooding areas generated by heavy rainfall inside the domain as well as by the runoff from the large catchment of Wadi Bili. ... mehrThe model supports the understanding of flow processes during and after heavy rainfall events. It can be applied to investigate structural mitigation measures such as retention basins and dams to create risk maps raising the awareness regarding flood-prone areas and is capable to become part of an early warning system.