232 / 2024-02-28 13:36:25

Numerical study of surge-river compound flooding in Shanghai: a case study of Typhoon Muifa (2212)

compound flooding,numerical modeling,tropical cyclone,FVCOM

Tropical cyclones (TC) can both lead to significant storm surges and bring heavy rainfall, resulting in high river discharges to coastal areas. The conjugation of them can lead to compound flooding in coastal cities, which may give rise to severe hazards. In this study, we simulate the compound flooding of Shanghai during Typhoon Muifa(2212), adopting a high-resolution numerical model covering the Shanghai mainland. The height of seawalls along the coastlines and floodwalls aside from the Huangpu River are considered carefully in the model. Our results show that.

China is significantly impacted by storm surge disasters, particularly in coastal regions where such events frequently lead to compound flooding, causing substantial economic losses and casualties. Using Shanghai as a case study, a high-precision numerical model was developed with the Finite Volume Community Ocean Model (FVCOM) to simulate inundation during storm surges. Specifically, the model was employed to assess the impact of Typhoon "Meihua" (2122), simulating the extent of inundation and the distribution of water depths in the affected area. The study examined scenarios involving runoff, typhoon impact, and their combined effects. It was found that the confluence of storm surge and riverine flooding significantly increased both the extent and depth of inundation. These findings highlight the potential underestimation of flood risks if the simultaneous occurrence of different types of flooding is not considered. These findings underscore the importance of considering the co-occurrence of multiple types of floods in flood risk assessment and management to avoid the pitfalls of fragmented responses.