Assessing long-term and short-term shoreline change of cockspur island in the Savannah River estuary

The shorelines of Cockspur Island, GA are constantly responding to natural and anthropogenic forces. In the fall of 2015, dredge spoil was placed on the north shore to protect cultural resources from rapid erosion. This study assessed both long-term and short-term shoreline change trends occurring on the island and at the experimental beneficial-use dredge spoil site, using GIS and sUAV surveying, to inform adaptive management strategies. The north and south shorelines were dominantly erosional over 85 years, at rates of -0.47 meters per year and -0.2 meters per year, respectively, and the east shoreline was accretionary at +3.79 meters per year. Based on a 0.5% per month volume loss rate over the 40-month period, the lifetime of dredge spoil placement is 14 years. However, because the elevation of the berm is decreasing as the deposit erodes landward, a shorter effective lifespan of 8 years is more likely.