ERS 7 - Large-scale flood risk assessments
Mostafa Farrag, home country Egypt
Host Institute: German Research Centre for Geosciences GFZ, Section 5.4 Hydrology
Large-scale flood risk assessments are needed for national policy developments, insurance industry, and large-scale disaster management planning. However only few studies have addressed the large scale flood risk assessment. One of the approaches used for large scale flood hazard assessment is to include the whole simulation chain starting from the observed or synthetic climate data followed by rainfall runoff then the 1D hydrodynamic routing model to account for the attenuation of the flood wave and the superposition of waves ant any confluence coupled with a 2D hinterland inundation model to simulate water movement in the floodplain and at the end of the chain comes a flood loss estimation model. Due to the large scale of the domain considered in the simulation with an appropriate spatial and temporal resolution to assure the numerical stability of the calculation simplifications have to be considered in the numerical schemes in each part of the model chain taking into account the stability, robustness and computational requirement to run the simulation within a reasonable time with a certain accuracy. In this research a new approach is developed for coupling the rainfall runoff model with the 1D-2D models to accurately route the upstream and lateral flows following the river network and using the sub-basin discretized results from the rainfall runoff model. Second objective of the research is to better represent the river cross section shape using 8 points. Third objective is to build a probabilistic dike breach model considering different failure mechanisms using fragility curves to simulate breach development, locations and outflow discharge. The last objective is to apply the model chain in some mitigation measures (intentional flooding of lower economic areas) to assess the effectiveness of the measure over the whole basin in terms of damage and risk reduction.