Abstract: Directions of Sand Transport, Anna Maria Key to Casey Key, Florida

L. D. Entsminger, W. F. Tanner

The directions of sand transport from Anna Maria Key to Casey Key were studied to discover the relative percent of littoral longshore transport. The directions of sand transport were divided into four classes: (1) toward the shoreline, (2) away from the shoreline, (3) parallel with the beach nearshore (less than 2.4 km), and (4) parallel with the shore offshore (2.4 km to 12 km). The values for the quantities of sand transported were obtained by map differencing. U.S. Coast and Geodetic Survey charts with hydrographic surveys spanning more than 20 years were used. The study region was divided into four areas each having little or no net loss or gain. The amounts of sand moved in each of the four direction classes were weighted according to volume. Area 1 was deleted from the final averages due to poor control. The other three areas showed the following: 6.0 percent of the sand moved toward shore, 49 moved offshore, 45 moved (nearshore) parallel with shore. Transverse transport, therefore, accounted for 55 percent of total sand transfer, and littoral transport, 45. This places clear limits on the use of the "a-b-c^hellip" model, requiring that "average" conditions nd "storm" (or hurricane) conditions be considered for distinctly different masses of sand and directions of transport.

AAPG Search and Discovery Article #90978©1975 GCAGS-GC Section SEPM Annual Meeting, Jackson, Mississippi