BARRIER ISLAND GEOMORPHOLOGICAL RECORD IN THE BACKBARRIER

Recent evidence suggests that backbarrier shorelines act as a historical record of island development. The geomorphology and structure of the backbarrier also control ecosystem development and an island’s transgressive response to relative sea level rise. Because we currently have a limited understanding of backbarrier geomorphology, this project seeks to link known process regimes to an island’s geomorphological history and thereby its foreseeable future. To define these linkages, the backbarrier shorelines of four United States National Seashores (Fire Island, NY; Assateague Island, MD; Santa Rosa Island, FL; and Padre Island, TX) are digitized from aerial imagery using the marshline as the shoreline indicator. This method ensures the inclusion of vital ecosystems often missed by more common indicators. The alongshore variation of these backbarrier shorelines is then quantified through wavelet analysis and each shape signature is spatially correlated to physical characteristics of the island such as wave climate, tidal range, and storm event frequency. The resulting classification system provides an improved understanding of backbarrier environments through simple quantitative analysis of aerial imagery and prediction of the morphological conditions that have shaped the barrier island under investigation.