Spatiotemporal Impacts of Climate and Demand on Water Supply in the Apalachicola-Chattahoochee-Flint Basin

Abstract

The transboundary Apalachicola-Chattahoochee-Flint (ACF) Basin in the southeastern United States has a long history of competition for water resources and litigation surrounding these conflicts. This case study applies the decision-scaling approach to explore the spatiotemporal impacts to water supply deficits in the ACF Basin from natural climate variability, from change in mean precipitation and temperature, and from shifts in municipal and industrial (M&I) water demand. System performance is characterized by reliability, vulnerability, and effective life (i.e., years until crossing an unacceptable performance threshold). The results indicate that long-term water supply reliability and vulnerability are sensitive to, in decreasing order of importance, changes in mean precipitation, mean M&I demand, and mean temperature. In the short term, natural climate variability causes the most uncertainty in vulnerability. Reliability (and the corresponding effective life) is uniform across the basin because of a shared water supply curtailments management system, whereas vulnerability (and the corresponding effective life) varies greatly. In particular, metropolitan Atlanta exhibits high sensitivity and vulnerability to stressors because of its location in the headwaters and high demand levels.