Philip M. Orton John C. Warner Shima Kasaei David K. Ralston 2026 <p><span>Numerical simulations with realistic forcing of fixed infrastructure for a proposed storm surge barrier for a lagoonal estuary, Jamaica Bay (New York, USA), are analyzed during typical forcing conditions to assess alterations to flow and sediment transport with the barrier open. Lagoonal estuaries are shallow and have modest watershed freshwater and sediment inputs, so sediment delivery is primarily from offshore by tidal transport. The storm surge barrier infrastructure across the inlet channel reduces cross-sectional area and increases tidal velocities, increasing frictional and form drag. The overall reduction in tidal amplitude is about 1%, but the quarterdiurnal M</span>₄<span>&nbsp;component decreases by 11%. The salinity and stratification in the estuary are only slightly modified by mixing by stronger velocities near the barrier. Sediment transport in the inlet scales approximately with tidal velocity cubed and net landward transport is driven by flood-dominant tidal asymmetry. Additionally, tidal asymmetry in the jet flow through barrier openings causes a divergence in sediment transport within several kilometers. The alterations to the tidal currents reduce sediment import to the bay by 20% for fine sand; transport of sediment with slower settling velocities is less affected, with reductions of 3% for medium silt and &lt;1% for fine silt. The study examined tidal exchange with an open barrier, but the overall impact also depends on barrier operations during major storm events. The impacts of barrier infrastructure on lagoonal estuaries are distinct from other estuary types due to their modest freshwater input, predominance of tidal transport, and offshore sediment supply.</span></p> application/pdf 10.1029/2025EF007875 en American Geophysical Union Storm surge barriers reduce seaward sediment supply to lagoonal estuaries article