Long-Term, Seasonal, and Event-Driven Sediment Movement on East Beach, San Salvador Island, Bahamas
Proceedings of the 6th Symposium on the Geology of the Bahamas and Other Carbonate Regions
East Beach is a modern, medium-energy shoreline located on the northeast coast of San Salvador Island, Bahamas. Stake and horizon profiles were made at 9 sites along a 1-km section of the beach in June, 1990, and every six months thereafter through January,1992. These observations appear to confirm that East Beach is a prograding shoreline, building onto the eastern shelf of the island. Seasonally corrected volume calculations indicate that between June, 1990 and January, 1992 approximately 14,000 m3 of new sand per kilometer were added to the East Beach system, with most of the sand likely derived from the nearshore shelf area. Visual evidence for progradation could be seen in the formation of a heavily vegetated berm along the backshore, that by June, 1991 had reached a maximum height of 40 cm before its destruction by the powerful storm that hit San Salvador in late October, 1991. Seasonal topographic measurements and volume calculations indicate a minimum of 8,600 m3/km of sediment moving offshore in response to higher average wave energies in the winter, and returning to build a wide foreshore and pronounced berm during the summer months. The late October storm battered East Beach with waves that entrained meter-sized blocks of coral, cut back the primary dune line by an average of 5.1 m, and washed over approximately 1,500 m3of sediment into the primary dune swale. Storm damage was measurably less severe at northern stations, possibly because of sheltering by Northeast Point and Man Head Cay, or by baffling action of the dense patch reefs offshore, or both.
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Brill, Andrew L.; Curran, H. Allen; and Fox, William T., "Long-Term, Seasonal, and Event-Driven Sediment Movement on East Beach, San Salvador Island, Bahamas" (1993). Geosciences: Faculty Publications, Smith College, Northampton, MA.
Reprinted from: Brian White (ed.), 1993, Proceedings of the 6th Symposium on the Geology of the Bahamas and Other Carbonate Region: San Salvador, Bahamian Field Station