Modeling of a compound flood induced by the levee breach at Qianbujing Creek, Shanghai, during Typhoon Fitow

摘要

Levee-breach-induced flooding occurs occasionally but alwayscauses considerable losses. A serious flood event occurred due to thecollapse of a 15?m long levee section in Qianbujing Creek, Shanghai, China,during Typhoon Fitow in October 2013. Heavy rainfall associated with the typhoonintensified the flood severity (extent and depth). This study investigatesthe flood evolution to understand the dynamic nature of flooding and thecompound effect using a well-established 2D hydro-inundation model(FloodMap) to reconstruct this typical event. This model coupled urbanhydrological processes with flood inundation for high-resolution floodmodeling, which has been applied in a number of different environments, andFloodMap is now the mainstream numerical simulation model used for floodscenarios. Our simulation results provide a comprehensive view of thespatial patterns of the flood evolution. The worst-hit areas are predictedto be low-lying settlements and farmland. Temporal evaluations suggest thatthe most critical time for flooding prevention is in the early1–3?h after dike failure. In low-elevation areas,temporary drainage measures and flood defenses are equally important. Thevalidation of the model demonstrates the reliability of the approach.