HR: 16:30h
AN: H34C-03    [Abstracts]
TI: Coastal System Interactions on Shackleford Banks, NC
AU: * Camann, E J
EM: ecamann@email.unc.edu
AF: University of North Carolina at Chapel Hill, Institute of Marine Sciences 3431 Arendell St, Morehead City, NC 28557 United States
AU: Wells, J T
EM: wells@vims.edu
AF: Virginia Institute of Marine Science, P.O. Box 1346, Gloucester Point, VA 23062-1346 United States
AB: An in-depth study of the beach-dune-nearshore system of Shackleford Banks, an undeveloped North Carolina barrier island located in the southern Outer Banks, has yielded insights about some of the complex interrelationships between these components. Although Shackleford is a small (~15 km long) island, it has a wide variety of beach-dune morphologies that respond differently to both `normal' conditions and storm events. Detailed monthly RTK-GPS surveys and several years of LIDAR data provide information about morphology and changes in the beach, dunes, and overwash. In general, the character of the island changes from a wider, taller, more stable western half to a narrow, overwash-dominated eastern half subject to frequent change. Sections with a continuous row of foredunes tend to experience repeated scarping of the beach and/or dunes. The thinnest portion of the island is also one of the least stable, and appears to be the location of a reversal in the dominant direction of longshore sediment transport. Sidescan and CHIRP data indicate that the nearshore of the eastern half of the island is reworked and sediment-starved, while the western half has numerous channel fill deposits and greater sediment availability. The outcropping of relict peat deposits (~300-900 years BP) and abundant fossil shell material provide further evidence of a lack of modern sediment cover in eastern sections. The far ends of the island differ from adjacent stretches of beach, with much of the western end experiencing rapid erosion, most likely due to inlet dynamics, while the eastern end of the island is accreting. The sheltering effect of Core Banks, Cape Lookout and Power Squadron Spit create typically calm conditions in this area, allowing sediment to accumulate. This is in contrast to adjacent areas, which experience greater wave energy and receive less sediment. The semi-annual simultaneous deployment of three electromagnetic current meters at western, central and eastern locations show that current velocities and wave heights and direction differ at the three areas, in spite of their proximity and shared wind climate.
DE: 4546 Nearshore processes
DE: 4558 Sediment transport
DE: 3020 Littoral processes
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting