Risk analysis of seawall overflowed by storm surge during super typhoon

• A collection of 42 typhoon tracks were designed based on the probability circle method.
• The water elevations and storm surges induced by all designed tracks with various center pressures were modeled.
• Overtopping probabilities of seawalls were estimated.
• Results of this study were valuable guidelines for seawall protection.

A numerical study based on the ECOMSED model was carried out to investigate the storm surge induced by super typhoon 5612 (WANDA) along Zhejiang coast, China. The modeled results presented good agreement with the observed data. According to the 70% probability circle method, 42 tracks were designed based on WANDA with various landfall locations and central pressures. Subsequently, overtopping probabilities of seawalls corresponding to each track were achieved. The results showed that variation of storm surge ranged from −0.04 to 0.04 m as the pressure increased/decreased by 5 hPa. The storm surge was easily influenced by the landfall location change with the same central pressure. The comparison of peak storm surge between modeled results and observed data at multiple stations were also illustrated. Moreover, in case of WANDA travelling within the 70% probability circle, seawalls between southern Taizhou and Wenzhou are faced with small effect; while seawalls located at southern Zhoushan and eastern Ningbo will be vulnerable and even suffered severe overtopping risk.