Abstract

Extreme storms can have a large impact on coastal sediment budgets and the character of strata preserved in the geologic record. Here, we investigate the impact of a cyclonic storm-surge flood and ebb on sediment transport in a microtidal beach barrier–shelf system. Hurricane Ike made landfall on the Texas (United States) coast on 13 September 2008. The accompanying storm surge flooded Galveston Bay with up to 5 m of water above sea level. The surge flood and ebb preferentially flowed over a low-elevation, bay-fronting spit known as the Bolivar Peninsula, destroying buildings and eroding sediments. Surge waters also flowed through Bolivar Roads tidal inlet, the main passageway through the barrier system that separates the gulf and the bay. Bathymetry, Chirp data, and samples were collected in Bolivar Roads tidal inlet 9 to 10 d after the storm, and we compare them here to data collected 4 mo prior. Additional data were collected offshore of Bolivar Peninsula in October 2008. Our results document the dominance of the storm-surge ebb in forcing sediment transport through the inlet, which is not considered in models of beach-barrier evolution. Shoreface sands appear to have been incised by the storm, and advected with beach-barrier sediments sufficiently offshore by the storm-surge ebb that they cannot be reincorporated, indicating a significant loss to the barrier system's sediment budget as a result of a single storm.

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