Expanding frameworks: Integrating vulnerability, exposure, and critical infrastructure to assess pluvial flood risks in New York City

Extreme precipitation events are increasing their frequency and intensity across the United States, posing growing risks to urban communities through pluvial flooding. Effective adaptation against pluvial flooding through structural and nonstructural measures requires understanding the spatial distribution of flood risks across urban populations and critical infrastructures. However, most flood risk assessments focus narrowly on the direct impacts of flooding and demographic exposures, overlooking disruptions that may result from indirect exposures and impacts to essential services like healthcare, education, welfare, and public safety. This study introduces an expanded risk framework to assess pluvial flood risk by integrating social vulnerability, population exposure, and the exposure of critical infrastructures across two citywide pluvial flooding scenarios that combine different precipitation events (moderate and extreme) and sea level projections. Analyses reveal vast differences in exposure between the scenarios. The extreme rainfall hazard scenario shows flooding in 3.8 times the area of the city compared to the moderate scenario, and affecting 3.1 times as many people. Exposure indicators for critical facilities and services show similar differences. Results show multiple locations where there is both high flood exposure and high social vulnerability. We also identify several neighborhoods where high flood exposure coincides with high social vulnerability and widespread risk to infrastructure, which can compound recovery challenges. These findings demonstrate the importance of broader framings of flood risk beyond population exposure to consider also social vulnerability and potential risks to critical infrastructure. Results further emphasize the need for equity-centered climate adaptation strategies in dense urban settings.