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Coastal bays and, specifically, back-barrier tidal basins host productive ecosystems, coastal communities, and critical infrastructure. As sea level continues to rise and tropical cyclones increase in intensity, these coastal systems are increasingly at risk. Developing a sediment budget is imperative to understanding how storm events affect the system's resilience, where net import of sediment indicates growth and resilience against sea level rise, and net export of sediment indicates deterioration. Using high-resolution numerical simulations, we show that intense storms import sediment into a system of bays in Virginia, USA. Duration and magnitude of storm surge are among the most important factors in sediment import, suggesting that intense storms increase the stability of tidal bays by providing the sediment necessary to counteract sea level rise. Since climate models project that tropical cyclones will increase in intensity in coming decades, our results have significant implications for the resilience of tidal bays and the future of coastal communities worldwide.

Plain Language Summary In order to counteract rising sea levels, a coastal bay needs to increase its bottom elevation by trapping enough sediment in salt marshes and tidal flats. People believe that storms are deleterious to coastal bays, but this is not necessarily true. In many coastal settings, intense storms are the main mechanism providing coastal bays with the sediments necessary to offset sea level rise. Here we show that intense storms provide sediments to the bay and marsh systems of the Virginia coastal bays, USA, thereby increasing their long-term stability.