Beach Aggradation Following Hurricane Landfall: Impact Comparisons from Two Contrasting Hurricanes, Northern Gulf of Mexico

Abstract

While the effects of major hurricanes have been intensively studied, less is known about the impact of the weaker but more frequent tropical cyclones, such as Hurricane Georges (1998). This hurricane, Category 2 at landfall, was non-typical in its effects. While high waves offshore and slow forward speed just before landfall resulted in island degradation, identical to that of Category 5 Hurricane Camille in 1969, the impact on the mainland was quite different. Only approximately 15% of the sand volume eroded by Camille in 1969 was removed from the Harrison County's mainland beach this time. Backshore areas of East Belle Fontaine Beach have prograded by 3–7 m. 20–90 cm vertical aggradation took place at several locations on its 10–45 m wide backshore. The short duration of hurricane-strength winds over the mainland and the availability of compensating sand supplies from adjacent sediment sources in the waning phase of the storm explain the limited extent of mainland shore erosion. Retreating shore bluffs and backfill from demolished bulkheads replaced eroded beach sand. Sand derived from artificial dunes on the backshore and from sand-rich nearshore areas have also mitigated effects of wave erosion.