Hydrodynamic model-based flood risk of coastal urban road network induced by storm surge during typhoon

Abstract

The occurrence of storm surges during typhoons results in the exacerbation of flooding incidents in coastal cities, with road networks vulnerable to inundation facing an intensified risk. This study presents a framework for assessing the flood risk of urban road networks resulting from the storm surge caused by Typhoon Mangkhut in Macau. Tidal changes in the Pearl River Estuary were simulated using a storm surge model integrated with a cyclone wind field. A high-resolution, small-scale urban hydrodynamic model, accounting for buildings and drainage systems, was further developed. Based on the flood characteristics within the model grid and the stability of people and vehicles, the threat posed by the typhoon-induced storm surge on urban roads was estimated. The results indicate that the maximum storm surge in the Pearl River Estuary during Typhoon Mangkhut exceeded 4.0 m, with approximately 25 % of roads experiencing flooding depth greater than 1.5 m. Most vehicles were at risk of instability, while fewer areas on the west coast of the Macau Peninsula presented a risk to human stability on flooded roads. The findings of this study contribute to the development of flood risk management strategies and emergency evacuation during typhoons.