Dynamic Flood Evacuation Modelling for Coastal Cities: A Case Study of Shanghai

Efficient evacuation during storm floods remains a critical challenge for coastal cities, primarily due to its dynamic and complex nature involving flood progression, human behavioral uncertainties, and emergency resource constraints.  Current evacuation models inadequately capture these multifaceted dynamics, limiting effective emergency planning. This study introduces an Agent-based Dynamic Coastal Flood Evacuation (DCFE) model that comprehensively simulates the interactions among flood dynamics, human behavioral responses, GIS-based transportation networks, and shelter systems.  Using Shanghai as a case study, we evaluate city-scale evacuations during a 1,000-year return period storm event. Our analysis shows that issuing warnings 12 hours before flood peak reduces casualty rates by over 25% compared to scenarios without early warning, while optimized decision-making can double evacuation efficiency. The results further reveal critical spatial disparities in evacuation performance due to inequitable shelter distribution. This integrated approach provides practical guidelines for enhancing evacuation strategies in coastal megacities worldwide.