Evolution of Erosion Hot Spots on a Barrier Island: Fire Island, New York

The distribution and evolution of local, shoreline features was examined by repeated mapping of the shoreline using a sub-meter GPS to map Fire Island from June to December. One region of erosion or "hot spot" was documented to migrate to the west, in the direction of the net longshore transport, at a rate of 2.1 m/day and then to the east at a rate of 4.2 m/day. Another shoreline feature followed the progression of a theoretical advection/diffusion model created earlier by other investigators to predict the migration of longshore sandwaves. This feature migrated to the west at 0.83 m/day. Similar features on the barrier island migrated to the west up to 51.5 m/day while others migrated to the east at rates up to 93.1 m/day. No trends in migration rate with the wavelength of the hot spot could be found. Rates tended to range between 1 and 100 m/day.