Assessing Urban Flood Resilience in Megacities through an Integrated GIS–Q-Rung Orthopair Fuzzy Framework of Socio-Economic and Urban Factors

<title>Abstract</title> <p>Recent extreme expansion of urban sites and infrastructures has intensified flood risks in major cities, raising the ultimate call to strengthen resilience against natural hazards. Thus, this study proposes a comprehensive assessment framework to evaluate flood resilience in urban areas by integrating 12 global and 81 sub-criteria related to socio-economic and urban characteristics. A novel decision-making model under uncertainty, structured on q-rung orthopair fuzzy sets combined with GIS, was developed to capture real-world complexities in resilience analysis of urban floods. Furthermore, the implemented sensitivity analysis experiments confirmed the robustness of the model, with strong consistency observed through correlation tests. The developed approach was applied to a critical district of Tehran, Iran’s capital and the largest city in Western Asia, which is a megacity highly exposed to flooding due to its location across three river basins. Using the weighted criteria, GIS-based resilience maps were generated and classified into five levels of resilience. The results indicate that 78.69% of the study area exhibits moderate or lower resilience, underscoring substantial vulnerability to future floods under shifting climate patterns. Management scenarios have been suggested to mitigate the adverse effects of the floods in urban areas that can be adapted to other flood-prone megacities worldwide.</p>