Integrating flood risk assessment and management based on HV-SS model: A case study of the Pearl River Delta, China

Global climate change has resulted in frequent extreme weather events in recent decades. The Pearl River Delta, one of the most developed regions in China, frequently faces the threat of flood disasters, causing significant human and economic losses. However, previous flood risk studies ignored the energy flow, material transfer and information transfer in the region, resulting in a disconnect between risk assessment results and management strategies, making it difficult to achieve the desired disaster prevention and mitigation effects. Thus, the HV-SS model was proposed with the aim of integrating flood assessment and management, thereby achieving more accurate and efficient risk management. The results showed that the majority of the study areas were under medium to high flood hazard levels, and their spatial distribution was closely related to natural conditions. The proportion of risk area was inversely proportional to the risk level, and the spatial distribution of flood risk exhibited a central-high and perimeter-low characteristic, with medium-risk surrounding the high-risk areas. Comparative verification, combined with the TOPSIS method achieved a matching rate of 89.89%, indicating that the assessment result was reasonable. The flood risk pattern constructed using the source-sink theory found that the primary risk sources were located in the central region and continuously transferred risk to surrounding areas through risk corridors. It is crucial to note that easily ignored risks were hidden around the risk nodes, and some reasonable flood management strategies were proposed. This study can provide a reference for regional flood risk assessment and management for sustainable development.