A social-ecological-technological vulnerability approach for assessing urban hydrological risks

In the context of urban population growth and climate change, and ever greater number of people are anticipated to face severe risks associated with extreme climate events; major ones are due to stormwater-related hazards. This study offers novel understanding of the complex nature of water-related risks in urban geographies by employing a Social-Ecological-Technological Systems (SETS) framework to assess vulnerabilities. Hydrology-informed urban risk index was developed, quantifying seventeen indicators from historical and modeled data on sewer overflow and flood events. The spatially explicit SETS-based approach identifies high-risk communities and hotspots where multiple vulnerabilities intersect and can serve as a valuable tool for guiding policy and decision-making to support more resilient urban futures. Our findings reveal that social vulnerability plays a critical role in determining the overall risk (R = 0.4), with the greatest impacts imposed on socially vulnerable communities. However, insights from the ecological (R = 0.2) and technological (R = 0.1) domains provide essential guidance for future risk reduction strategies-such as upgrading outdated sewer infrastructure and exploring green space potential for run-off mitigation. The framework proposed is generalizable to other cities facing similar environmental challenges, highlighting its potential as a foundational tool for policymaking to reduce risks associated with extreme climate events.