Agent-based Modelling of Urban Rainstorm Flood Disaster Early Warning Strategy Simulation
Disaster early warning plays an important role in disaster reduction management by proactively dissem-inating disaster information to guide residents in taking timely evacuation actions,thus effectively reducing disas-ter losses and casualties.The dynamic response process of residents to disaster early warning information and the assessment of the effectiveness of different flood disaster early warning strategies are pressing issues.This paper proposes a simulation method for urban rainstorm flood disaster early warning strategies based on Agent-Based Modeling(ABM).Firstly,three warning strategies are established:rainfall forecast-based,flood inundation-based,and population exposure-based.Secondly,individual risk perception is assessed by considering a variety of socio-demographic characteristics,and a probabilistic model of individual travel decision-making is constructed.Based on this,an agent-based model for urban flood disaster early warning strategies is developed.Finally,taking Futian District in Shenzhen,China as a case study,residents'travel behavior and flood risk are simulated and analyzed with different flood warning strategies under 20-year,50-year,and 100-year return period rainstorm scenarios.The results show that:(1)The ABM simulation model,considering residents'perception of flood disaster risk and the probability of individual travel decision-making,accurately simulates residents'travel response behavior and changes in flood disaster risk under different warning strategies.It provides a scientific and comprehensive evalua-tion of the effectiveness of urban flood disaster early warning strategies;(2)Different warning strategies lead to significant differences in population travel response behavior,resulting in varying effectiveness in reducing urban rainstorm flood disaster risk.Faced with a 20-year rainfall scenario,flood inundation-based and population expo-sure-based early warning strategies help residents in the study area quickly identify high-risk areas,significantly reducing the risk to buildings and roads.Faced with a 20-year return period rainstorm scenario,the study area shows minimal changes in residents'travel behavior under rainfall forecast-based warnings.However,flood inun-dation-based,and population exposure-based warning strategies help residents rapidly identify high-risk areas,significantly reducing the number of people heading to red and orange warning zones.This results in a notice-able decrease in risks to buildings and roads;(3)Under different rainstorm scenarios,the effectiveness of various flood disaster early warning strategies varies.In the face of smaller rainstorm scenarios,refined flood disaster early warning strategies,such as flood inundation-based,and population exposure-based,demonstrate effective-ness in reducing urban flood disaster risk.However,when dealing with extreme rainstorm scenarios,adopting a unified flood disaster early warning strategy,such as rainfall forecast-based,is more effective than a refined warning strategy.Therefore,urban flood disaster early warning systems should be tailored to local conditions and varying circumstances,establishing a graded,zonal,and scenario-based warning system.