298 - Declining Reservoir Storage Capacity in the US – What can Existing Data Tell Us?

Global per capita water storage has declined over the last several decades, with current estimates placing us in roughly the same position as the 1960’s. Dam decommissioning and reservoir sedimentation result in a net storage loss, which threatens the sustainability of water supply systems, energy generation, and flood control. Despite the risks that storage loss pose to the communities that depend on these reservoirs, data scarcity has long been a challenge for assessing the impacts of sedimentation and storage reduction rates over time. However, data compilation efforts and advances in spatial and temporal resolution of satellite data have enabled better understanding of reservoir bathymetry, volume fluctuations, and sediment loading, and storage reduction dynamics. We evaluate historical reservoir sedimentation surveys alongside a variety of remote sensing data products to describe data coverage and suitability for evaluating the impacts of sedimentation on storage capacity at existing reservoir facilities in the US. Specifically, we focus on multi-purpose reservoirs used for energy generation and those that could be considered for hydropower development. We then evaluate published storage information against reservoir services and local hydrology/watershed characteristics to describe regional and operations-based patterns. This analysis identifies types of systems where additional data collection and modeling advances are particularly needed and provides valuable insight for the long-term management of critical water infrastructure.