Managing Cascading Impacts on Critical Infrastructure in Stockholm, Sweden

Climate change and urbanization have increased the frequency and severity of flood events in many cities, highlighting vulnerabilities from the interdependence of critical systems in urban environments. In highly connected cities, flood impacts rarely remain localized but instead propagate across infrastructures, services, and social systems, generating cascading effects that amplify societal, economic, and environmental consequences. Despite growing recognition of compound and cascading risks, most flood risk studies continue to focus on direct impacts or single-sector analyses, with limited capacity to capture how flood-triggered disruptions evolve and interact across interconnected systems in space and time.

To address this gap, this study develops an integrated framework and a web-based tool for analysing flood-driven cascading risks, demonstrated through Stockholm city. Long-term and real-time flood risk maps provide geospatial hazard inputs that trigger infrastructure failure propagation across water, electricity, and transport systems.

Applying this framework helps identifying spatial patterns of cascading flood impacts, revealing hotspots where interconnected systems exhibit heightened vulnerability to extreme events. These impacts demonstrate how indirect effects can dominate overall risk, often exceeding direct flood damages. By making complex cascade dynamics transparent and explorable, this approach supports improved situational awareness, facilitates cross-sectoral dialogue, and enhances decision-making for flood risk management and adaptation planning. The framework contributes to advancing the assessment of cascading risks from extreme hydrological events and provides a foundation for more resilient and integrated approaches to managing flood impacts in a changing climate.