Monitoring Beach Renourishment along the Sediment-Starved Shoreline of Grand Strand, South Carolina

In this paper, we examine temporal and spatial beach profile volume changes, sediment budget changes, and side-scan sonar images at nourished beaches of northeastern South Carolina. Results of bulk volume change indicate that most sands eroded from the subaerial beach section remain and circulate within the coastal system. The results also indicate more active sediment exchange between the nearshore and offshore zones than expected, indicating that the offshore can be both a sink and a source for the nearshore morphologic change. Our profile volume change results do not show a unidirectional net southerly transport pattern in the study area during the initial postnourishment period. Instead, results show that the net downdrift direction alternates along the shore and that longshore volume drift patterns are often disrupted by the seaward cross-shore transport events that occur at erosional hotspots. Prenourishment erosional patterns, particularly local areas of elevated erosion rates, were re-established after nourishment. Furthermore, those erosional locations often correspond to the offshore locations of paleoriver channel fill sands with low relief, indicating existence of the specific seaward transport pathways along the shore in the study area.