Integration of Stability Functions Into a Transport Flood Risk Modelling Framework

Abstract

The increasing frequency of urban flooding due to climate-induced extreme rainfall highlights the critical need for adaptive emergency preparedness. Maintaining public access to essential services during such events is critical, yet flood risks to the transport network can compromise public safety and mobility. This study employed a combined depth-velocity stability function to assess the risks posed to individuals navigating floodwaters and evaluates accessibility to key service points using basic risk-avoidance criterion. Transport network analysis compares the no-flood, depth-only and depth-velocity risk scenarios. Analysis indicates that risk assessments solely based on flood depth significantly underestimate localised risk in urban environments. At the flood peak, high-risk areas for vehicles and pedestrians are underestimated by 18.2% and 83.3%, respectively, while these increase to 36.4% and 240.0% for medium-risk areas. Applying depth-velocity thresholds determined the obstructed roads and inaccessible zones. Risk-adjusted alternative routes were generated considering the obstructions, providing viable paths for the public to use during the flood peak. The integrated approach, combining flood modelling, stability functions and network analysis offers a framework that can significantly contribute to the improvement of risk resilience and transport management for flood-prone cities.