The combined influence of extreme weather and sea-level rise on water damage around the entrance of rail transit in coastal areas

The intensity and frequency of extreme weather events are increasing globally. Concurrently, future sea-level rise (SLR) and resulting storm surges pose significant threats to coastal cities and their rail transit systems. This paper proposes a calculation model to assess water damage around rail transit entrances caused by the convergence of extreme rainfall, storm surge, and sea-level rise. The model is applied to Wanqingsha Station of Guangzhou Metro Line 18 in China to predict the risk of water damage to around rail transit entrances using the actual surge process of Typhoon Mangkhut combined with various SLR scenarios. The results indicate significant variability in surface ponding and water intrusion processes as SLR changes with storm surges. When the SLR is between + 0.8 ~ 0.88 m, the maximum ponding depth and total intrusion water volume increase sharply. The location of the rainfall peak can significantly affect the escape time for people, with the escape status shifting from safe to unsafe in a very short period under storm surge conditions. The highest risk of water damage occurs when the rainfall peak coincides with the peak of the storm surge.