STATE-OF-THE-ART ANIMATION DEPICTS THE EVOLUTION OF A HISTORICAL INLET, GEORGETOWN COUNTY, SOUTH CAROLINA

We present a state-of-the-art photo-realistic 3-D animation to help visualize barrier evolution and the life cycle of New Inlet along Debidue Island, South Carolina. New Inlet was one of several historical inlets that existed between Murrells and North Inlets. Its location was depicted on maps dating back to the late-1700’s, when it delineated the property boundary between two parcels of land, but by 1820 the channel had closed. The geomorphic expression of this former inlet has since been obliterated by barrier progradation, dune growth, and vegetation, and the location of the property boundary is now in question. Initially, historical maps, plats, and aerial photographs were used to approximate the position of the inlet. Subsequently, a detailed geophysical and sedimentological dataset was acquired, including more than 5 km of ground-penetrating radar transects, 14 vibracores, 13 pulse-auger cores, and a number of tree cores. Radiocarbon dating of ten organic samples provided a chronology for the evolution of this coastal system. The thalweg of the channel structure was identified at more than 3 m below the ground surface with a lag deposit containing moderately sorted, medium-to-coarse sands with quartz pebbles and shell hash characterizing the base of the paleo-channel. Our data indicate that during its existence, New Inlet was a small feature approximately 1 m deep and more than 50 m wide. Its dimensions are characteristic of many modern-day ephemeral inlets. The integrated historical, topographic and geological datasets formed the basis for the animation depicting various stages of coastal evolution focusing on the barrier-inlet interaction.