USING NEARSHORE GEOPHYSICS TO UNDERSTAND POST-STORM BEACH RECOVERY: LINKS TO SPATIALLY-VARIABLE WAVE RAVINEMENT?

It is widely recognized that sediment availability plays a critical role in coastal evolution. At large time and space scales, it governs the volume of sediment available for barrier island formation. At medium scales, it has been shown to influence decadal coastal change patterns. However, the importance of sediment availability at interannual and event scales remains largely unexplored. Further exploration of nearshore geology, specifically alongshore variability in wave ravinement formation, could improve understanding of the response and recovery of the coastal zone over event to interannual time scales.

At Fire Island, NY, decades of study have established a connection between the geology of the inner shelf and long- and medium-term coastal behavior. An extensive data set and the significant impact of Hurricane Sandy on the island provides the opportunity to improve understanding of the role of nearshore sediment availability in coastal recovery. During June 2014, in collaboration with the U.S. Army Corp of Engineers Field Research Facility, high-resolution seismic profiles were collected along ~30 km of the island, extending from the beach to ~2km offshore and spanning a variety of previously documented shoreface morphologies. The morphology and character of the shoreface wave ravinement surface varies spatially and with depth, resulting in variability in shoreface sediment available for beach recovery. Geophysical data are compared to the results of repeated shoreface bathymetry surveys and beach recovery data to explore links between nearshore geology and morphodynamics and upper shoreface recovery.