HR: 0800h
AN: OS21B-1226    [Abstracts]
TI: The South Carolina Coastal Erosion Study: Numerical modeling of circulation and sediment transport in Long Bay, SC
AU: * Warner, J C
EM: jcwarner@usgs.gov
AF: US Geological Survey, 384 Woods Hole Rd., Woods Hole, MA 02543 United States
AU: Sullivan, C
EM: csullivan@usgs.gov
AF: US Geological Survey, 384 Woods Hole Rd., Woods Hole, MA 02543 United States
AU: Voulgaris, G
EM: gvoulgaris@geol.sc.edu
AF: University of South Carolina, Department of Geological Sciences, Columbia, SC 29208 United States
AU: Work, P
EM: paul.work@gtsav.gatech.edu
AF: Georgia Institute of Technology, 210 Technology Circle, Savannah, GA 31407 United States
AU: Haas, K
EM: khaas@signals.gtrep.gatech.edu
AF: Georgia Institute of Technology, 210 Technology Circle, Savannah, GA 31407 United States
AU: Hanes, D M
EM: dhanes@usgs.gov
AF: US Geological Survey, 400 Natural Bridges Drive, Santa Cruz, CA 95060 United States
AB: Long Bay, South Carolina, is a heavily populated coastal region that supports a large tourism industry. Sand resources are important for both recreation and coastal habitat. Earlier geological framework studies have identified a large sand deposit oblique to the shoreline, oriented clockwise in the offshore direction. This sand feature is ~ 10 km long, 2 km wide, and in excess of 3m thick, possibly providing a source for beach nourishment material. Objectives of this study are to describe the physical processes that control the transport of sediment in Long Bay, specifically off the coast of Myrtle Beach, South Carolina. Specifically we seek to 1) measure and model the oceanographic circulation in the region, 2) identify the processes that maintain the presence of the offshore sand feature, 3) quantify the control that the shoal exerts on the nearshore through changes in wave energy propagation, and 4) identify consequences of removal of the offshore sand feature. Both observational and numerical experiments are used to study the oceanographic circulation and transport of sediment. The observational study is described in an accompanying poster and consists of eight sites that measured tides, surface waves, currents, salinity, temperature, suspended sediment concentrations, and bed forms from October 2003 to April 2004. Numerical modeling for circulation and sediment transport in the study region uses a new version of ROMS (v2.1) that now includes transport of multiple grain sizes, coupling of sediment transport to wave bottom boundary layer models, and evolution of the bottom morphology. The SWAN model is used to compute wave propagation. Results indicate that currents in the study area are strongly influenced by both tidal motion and wind driven setup / setdown. The presence of the offshore sand feature alters the residual flows in the region. Sediment transport is more significant during periods of sustained strong winds that generate local waves. Wind direction plays a key role in determining the direction and magnitude of sediment transport.
DE: 4255 Numerical modeling
DE: 4558 Sediment transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting