Changes in Fetch Limited Barrier Islands along the Delaware Bay coast of New Jersey

Abstract:

Fetch limited barrier islands protect vast swaths of sensitive intertidal biomes in the Delaware Bay, but little is known about their specific response to sea level change. The continued viability of barrier islands is threatened in the face of rising seas and coastal erosion. To assess the response of barrier islands in Delaware Bay to sea level rise, we quantified shoreline migration and changes in their size using historic maps and aerial imagery. We establish a historical record of changes of barrier island area and rates of shoreline migration, we built a time-series analysis using aerial images and historic maps of Delaware Bay along the coast of New Jersey, dating back to 1970. Since 1970 the barrier islands have decreased in size, and the region experienced an average shoreline transgression rate of 3 m/yr. However, some areas are experiencing substantiality higher rates of shoreline migration, while other areas remain relatively stable. We interpret this as resulting from varying wind energy and currents in the bay. Using our measured rates of shoreline migration and NOAA wind data for the region, we developed a GIS model examining how wind and current energy may contribute to variation in rates of shoreline change in the region. This information allows us to better anticipate the effects of sea level rise on the fragile estuarine system.