VANISHING ISLANDS: CHANGING FETCH LIMITED BARRIER ISLANDS IN THE DELAWARE BAY

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 changes in barrier island shape and and position using historic maps and aerial imagery. Over the last 45 years the barrier islands have substantially 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, currents, and/or inlet migration in the bay. Using our measured rates of shoreline migration and NOAA wind and current 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.