Characterizing the Atmospheric Conditions Leading to Dam Overtopping in the Eastern United States

This study uses catchment-level statistical characterization of reanalysis and precipitation datasets to create a typology of 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 conditions 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.

This analysis divides the US eastern seaboard into four regions to examine the meteorological events within a 30-day period prior to a dam’s hydrologic incident. Initial analysis of the northeast sub-region found that although quasi-stationary fronts (frontal) or tropical cyclones (TC) present their own risk, compound events combining the two were most immediately associated with numerous dam failures over a broad region. However, catchment-level precipitation analysis further highlighted that the basins that had failures during these TC/frontal events also had numerous smaller precipitation events in the timeframe leading up to the incident. This longer tendency towards higher precipitation is associated with persistent large-scale patterns within the 14 days prior to the event. Ongoing analysis of the other sub-regions within the study area will further characterize variations across the region, as well as provide deeper insight into processes that determine how precipitation is distributed within the catchment.