Abstract: Current flood risk analysis is mainly based on typical design standard floods, which cannot meet the needs of actual flood control management. In order to improve the real-time flood risk analysis and adapt to the dynamics of flooding, in this study, a dynamic real-time flood risk analysis framework was designed. In this framework, one-dimensional and two-dimensional dynamic coupled hydrodynamic numerical methods were used to couple the dyke breach model, and then a flooding simulation model was established in Qiaosang flood protection area. Through improvement, the flood inundation conditions can be simulated and analyzed based on real-time water conditions or arbitrary design floods. By flexibly set the boundary conditions and dynamically set the breach function, the flooding process of the protected area after single breach or combined breach was calculated. According to this framework, the dynamic real-time flood risk map compilation and management application system of the Qiaosang flood protection area was developed, and further verified by using the historical flood data. The verification results show that the absolute errors of the highest water level measured at Makou Station, Sanshui Station, Da'ao Station, and Ganzhu (1) Station during the 2008-06 flood and the highest water level calculated by the model are -0.10 m, 0.10 m, 0.09 m, and 0.04 m, respectively, which meet the requirements of the precision of flood simulation. The model was used to calculate the flood discharge and the water level inside and outside the breach of Jianggen dike when the flood occurs once every 200-year in Xijiang River, when the simulated width of the breach was 168 m, the maximum flow of the breach reached 5 190 m³. The village inundation caused by the flood of 3 h, 6 h and 24 h after the dyke breach was analyzed, and the results satisfy the rationality analysis.

Key words: dynamic flood risk map, real-time flood risk, hydrodynamic model, dike breach flood