Modeling flood propagation and cascading failures in interdependent transportation and stormwater networks

This study addresses the challenge of modeling flood propagation and cascading failures in geographically interdependent transportation and stormwater systems, filling a critical gap in the literature by effectively capturing the temporal progression and spatial distribution of failures in interdependent systems. We developed a contagion-based Susceptible-Exposed-Flooded-Recovered (SEFR) model to monitor flood propagation dynamics within these interconnected systems. We established a spatial interdependency threshold for transportation and stormwater systems using a multilayer network representation and incorporated the state-of-the-art Hydrologic Engineering Center's River Analysis System (HEC-RAS) to generate reliable flood data. The SEFR model combines the topological characteristics of the multilayer network with simulated flood data to accurately model the propagation of flood damage and cascading failures. Focusing on Norman, Oklahoma, we calibrated the SEFR model using the HEC-RAS 2D flood simulation data for a major precipitation event on July 27, 2021. Results demonstrate the SEFR model's ability to identify the spatiotemporal variations in flood propagation, highlighting critical infrastructure components at risk, including specific road segments and stormwater system elements vulnerable to cascading failures during flooding events. The findings provide new insights into interdependent system resilience and inform intervention strategies to mitigate adverse flooding impacts, enhancing the robustness of critical infrastructure against natural disasters.