Investigating the impact of extreme precipitation induced urban flooding on road network disruption

Flooding is among the most prevalent natural hazards worldwide, with increasing frequency and devastating impact. Urban floods are severe in Indian cities due to the culmination of changing climate, rapid urbanization, and intensive population growth. Transport infrastructure such as roads underpins economic activity enabling goods and human mobility. Evaluating the response against urban flooding is critical as disruption of the road system can result in cascading effects. The recent advancements in assessing the direct impact of urban flooding on road infrastructure are well explored. However, we lack a systematic approach to model and evaluate the direct, intangible, and indirect effects of extreme precipitation-induced urban flooding on road infrastructure systems in urban areas with unplanned drainage systems. Here in this study, we model the interaction between urban flooding and road transportation systems by integrating a hydrodynamic model with a network science approach for the coastal city of Kozhikode, India. We evaluated the response of the combined sewer drainage system against extreme precipitation events through the 1D-2D coupled flood model. While also identifying the resulting flood inundation characteristics- extent, propagation, and depth. Flood modeling results indicate the inundated roads and functionality loss of the road system for extreme precipitation events. Our initial assessment highlights that highly localized road network submergence due to flood inundation has a widespread and prolonged disruption in the system. The integrated framework and network functionality measures could help in future resilience assessment and in devising effective planning strategies for hazard mitigation in urban areas.