BEACH GEOMORPHOLOGY STUDY, DEWEES ISLAND

Beach Geomorphology Study, Dewees Island

Barrier islands are extremely dynamic environments. Millions of dollars of development are threatened each year by processes that cause erosion. Conversely, certain areas within an island system experience accretion, which provides a buffer against these destructive processes. Developing a model of barrier island change can facilitate better coastal management decisions in the future. Dewees Island is a 3 mile long barrier island located 11 miles north of Charleston, South Carolina. The Beach Geomorphology Study is a full year study during which the entire beach system of Dewees Island has been surveyed every other month. Laser level technology and handheld GPS units have been utilized to collect multiple position and elevation values along 49 shore-normal transects. Three dimensional raster images of the data have been created using Geographic Information System (GIS) software. Comparison and analysis of these three dimensional models can indicate areas of change and approximate the volume of change. The study began in February 2006. Final analysis and quantification of sand volumes will be concluded in March. Based on observed patterns, shoreline regression appears to dominate the center portion of the island, while accretion is occurring along the northern and southern extents of the beach. The rate of erosion appears to have accelerated during the period of study. Extending the study over the next several years on at least a semi-annual basis would offer much more information on the overall trend.