Vulnerability assessment of future flood impacts for populations on private wells: utilizing climate projection data for public health adaptation planning

Climate change hazards, like extreme precipitation and flooding, are expected to adversely impact drinking water sources. People dependent on private wells are particularly vulnerable. Increasing availability of climate projection data can facilitate assessments of future vulnerability; however, there are challenges for end users. We developed a novel yet accessible approach for applying climate projection data (2050–2074) to the estimation of flood risk to Minnesota populations dependent on private wells for drinking water. Results were compiled in a geographic information system (GIS)-based overlay analysis with data representing potential nitrate contamination and infant population projections resulting in a county-level composite vulnerability index (CVI). Our findings show that by mid-century, 80% of Minnesota counties with over 20,000 flood-sensitive private wells will experience June extreme rainfall levels historically associated with disaster-level flooding. Counties with very high to high CVI are located mainly in central and southern regions and will account for over 60% of the state’s overall population growth by mid-century underscoring the need to expand private well protections. Climate projection data from global climate models can be used by public health professionals to determine future precipitation extremes and applied to population vulnerability assessments to inform public health planning and response to future climate changes.