Category 5 Hurricane Michael made landfall near Mexico Beach, Florida on October 9, 2018, with measured high water marks (HWMs) reaching 7.2 m NAVD88. The town itself received great damage, with many areas destroyed down to the foundations. In this study, we document the storm and its effects on the greater Mexico Beach area: hazard, structural damage, and their relationships. Wave and surge damage was nearly total for low-lying properties, but damage decreased greatly with increasing elevation. Major wave and surge damage was noted in Federal Emergency Management Agency (FEMA) X zones, which are out of the 100-year floodplain, and it is suggested that the 100-year storm is a deficient measure for categorizing flood risk.

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Maintaining navigable waterways through dredging is vital to society and the economy, especially as global transport and cargo loads increase. Decision makers require rapid techniques to evaluate potential placement alternatives for the dredged sediment. When appropriate, dredged sediment can be placed in the nearshore as a berm or a mound, often with the expectations of dissipating wave energy further offshore and inducing shoreward sediment transport. However, the exact placement area requires the water depth, hydrodynamic climate, and sediment size to be considered. Previous work used the well-known depth of closure concept to assess berm stability. A web-based Sediment Mobility Tool (SMT) was recently developed to assess the probability of sediment transport and direction with the knowledge of a few simple parameters. In this study, 20 historical projects that placed dredged sediment in the nearshore are reviewed to evaluate the depth of closure equations predictive capability on berm stability. The frequency of sediment mobilization and cross-shore transport direction are estimated for nine historical projects. The evaluated projects represent a diverse range of construction methods, placement geometries, sediment characteristics, and wave climates. The techniques used to estimate sediment mobilization frequency and transport direction are universal. These techniques are an essential step for engineers and planners to evaluate the potential volumes of dredged material that nearshore placement operations might yield to nourish a beach profile.

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