County Level Flood Risk Assessment reveals Rural Appalachian Communities of Southwest Virginia Face Disproportionate Riverine Flood Exposure and Infrastructure Vulnerability

Abstract

Riverine flooding poses a disproportionate risk to rural Appalachian communities in southwest Virginia, where mountain terrain forces roads, buildings, and power lines into narrow river valley corridors, leaving community infrastructure vulnerable and residents cut off from emergency services. However, existing flood risk assessments have predominantly focused on urban and coastal settings, leaving rural mountain communities largely unexamined. This study presents a county-level flood risk assessment targeting rural southwest Virginia Appalachian counties, quantifying flood exposure and direct damage costs for buildings, roads, power grid infrastructure, and resident populations. We intersect Federal Emergency Management Agency (FEMA) Special Flood Hazard Area (SFHA) polygons with infrastructure inventories derived from Microsoft Building Footprints and OpenStreetMap, alongside population data from the 2020 US Decennial Census Bureau. Direct damage costs are estimated using depth-damage functions for residential buildings and empirical fragility curves for power infrastructure. Median road exposure across the study region is 6.6%, 210% of the Virginia statewide median 3.1% and the region’s median building exposure is 4.9%, 327% of the Virginia median 1.5%. In comparison to the Virginia per-resident damage cost average of $1,101, the region yields a cost of $1,777, targeting populations with limited capacity for recovery. These findings highlight the vulnerability of Appalachian communities, a dynamic that may be replicated across regions throughout the Appalachian highlands and beyond. Addressing this vulnerability will require flood risk frameworks that move beyond asset level damage analysis and explicitly account for how infrastructure disruptions can physically isolate rural communities.