Author(s): Mingyan Wang; Philippe Gourbesville; Paguedame Game

Linked Author(s): Mingyan Wang, Philippe Gourbesville

Keywords: Hydrological model; Hydraulic model; Topography resolution; Flood management

Abstract: With the increase of extreme rainstorms triggered by global climate change, the flood risk has become a major concern in French Mediterranean region. The deterministic distributed hydrological model MIKE SHE and hydraulic model MIKE 21 FM both play important roles in flood forecast and management. The topographic resolution is a key component for the accuracy of flood simulation. It represents the characteristics of the basin especially the slope distribution and the representation of the stream network. This study takes the Cagne catchment, on the French Riviera as study area. It covers 96 km² area with the elevation ranges from 0 m to 1535 m and it densely urbanized with high risks of inundation in the downstream area. The simulation results from the MIKE SHE hydrological model (coupled with MIKE 11 model) with different topographic resolution – 30 m and 20 m, and simulation results from MIKE 21 FM hydraulic model with different topographic resolution – 5 m, 10 m for river bed and 20 m, 30 m for floodplain - are analysed to evaluate the impacts of topographic resolution on the model accuracy and the assessment of uncertainties. The optimal resolution considering both accuracy and computational time is defined considering the use of models in real time. These two models described here are contributed to the decision support system in Cagne catchment, and the methodology presented can be used in any other catchment facing similar challenges.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221427

Year: 2022