Assessing flood resilience of urban rail transit systems: Complex network modelling and stress testing in a case study of London
Wei Bi, Jennifer Schooling, Kristen MacAskill
Abstract
While the growing prevalence of extreme floods worldwide constantly compromises the service delivery of urban rail transit systems (URTSs), limited research attempts to measure the resilience of URTSs to flood disruptions. This study marks the first quantitative assessment of URTS flood resilience, focusing on dynamic operational performance of service delivery under realistic flood disruption scenarios. A model is tailored to incorporate a broader range of real-world factors into complex network modelling than adopted previously, including physical URTS network features, plausible flood disruption scenarios, and resourcing for recovery. The results of the London URTS case study suggest that the loss of satisfied travel demand is approximately 1.8 million, 4.2 million, and 7.2 million for the 30-year, 100-year, and 1000-year floods, leading to anticipated revenue loss of £3.1 million, £6.8 million, and £11.4 million, respectively (subject to modelling assumptions). This study highlights that the popular normalised resilience index can capture system performance loss but not necessarily recovery time: this matters when there is a long tail to the recovery process. This study provides a meaningful quantitative approach to assessing the current level of system resilience and lays the groundwork for testing the effectiveness of potential interventions for disaster risk reduction in operation and management.