Risk assessment based on Bayesian Network for the typhoon-storm surge-flood-dike burst disaster chain: A case study of Guangdong, China

Study region: The Modaomen Waterway to Makou Station at the Pearl River Basin, a region of southeastern China Study focus: The consequences of the disaster chain are governed by various variables such as typhoon track, typhoon intensity and engineering conditions. The currently commonly used risk indicator methods have limitations in addressing the uncertainty relationships among disaster elements. This study establishes a complex network structure of disaster chains based on the risk transmission and response between different types of disasters during the disaster chain process. On this basis, a risk assessment model based on Bayesian Network for the TSFD disaster chain is constructed to evaluate the risk performance of the TSFD disaster chain under various scenarios (different conditions), thereby proposing corresponding disaster prevention and mitigation suggestions. New hydrological insights for the region: Typhoon intensity, typhoon path and astronomical tidal cycle can have significant impacts on the risk of the TSFD disaster chain. Astronomical tidal cycle and typhoon path have a more significant impact on storm surge disasters than on flood disasters, while the opposite effect is found for typhoon intensity. Severe typhoon coupled with spring tide causes a higher risk of storm surge and flood disaster than super typhoon coupled with neap tide. The probability of average storm surge is increased by 15.0 %. This is because the degree of storm surge, flood and dike burst damage does not directly correspond to the typhoon intensity. While there is a strong positive correlation between the magnitude of storm surge and flood disasters and typhoon intensity, they are also influenced by astronomical tide and the amount of rainfall from typhoon. It is also noted the timely supply of flood-control materials can reduce the degree and risk of dike burst, but the probability of dike burst is reduced by approximately 2 % in a high-intensity typhoon event or during spring tide.