Spatial Assessment of Urban Flood Vulnerability in Polk County, Iowa Using a Social–Ecological–Technological Framework

Flood impacts are shaped not only by environmental or economic consequences but also by the social, ecological, and infrastructural conditions that influence how communities experience and recover from hazards. This study aims to assess multi-domain flood vulnerability across Polk County, Iowa utilizing a Social–Ecological–Technological Systems (SETS) framework. Eighteen indicators were standardized and aggregated to produce domain-specific and composite indices, which were evaluated independently from mapped flood exposure at the census block group scale. Results show that social, ecological, and technological vulnerabilities exhibit distinct and non-coincident spatial patterns, while composite indices reveal broader zones where multiple weaknesses co-occur. The highest compounded susceptibility is concentrated in the Des Moines urban core and along the Des Moines River corridor, although each domain highlights different localized patterns across the county. Weak correlations between vulnerability scores and flood extent support that intrinsic susceptibility and hydraulic exposure represent separate and complementary processes. Overall, the framework provides a transparent and transferable approach to support targeted mitigation, planning, and resilience strategies in flood-prone urban communities.