A multi-scale analysis of atmospheric processes associated with dam overtopping events in the Eastern United States

This study uses WRF high-resolution numerical modeling case analysis and catchment-level statistical characterization of reanalysis and precipitation datasets to examine the evolution atmospheric conditions associated with hydrologic dam incidents in the eastern United States. Extreme precipitation elevates the risk of dam overtopping, which is the main cause of a third of US dam failures. As the intensity of precipitation is predicted to increase in future climates, understanding the evolution of precipitation-generating features within the atmospheric system, alongside the hydrologic response leading up to the failure, is a crucial initial step in properly characterizing and predicting the risk of dam failures during a range of weather events. Case study analysis reveals that the Appalachian Mountains have the potential to play a role in these events, even at distance from the terrain itself, owing to complex interactions between orographically-blocked flows, fronts, and other meteorological phenomena like tropical cyclones. Statistical analysis of four subregions of the US eastern seaboard 30-days period prior to a dam’s hydrologic incident further highlight that combinations of these phenomena present more risk for high numbers of failures than each phenomenon alone. Ongoing analysis of the sub-regions seeks to characterize variations across the region, identify the role of persistent atmospheric patterns, and provide deeper insight into processes that determine how precipitation is distributed within the catchment.