Barrier Island Morphological Response to Natural Disturbances and Human Dune Modifications: A Comparative Analysis of Developed and Undeveloped Regions of the Outer Banks, NC

Barrier islands shift dynamically, often influenced by wind, wave, tidal, and storm forces. Overwash occurs naturally from storm surge, but can be hindered by alteration to the coastal landscape by humans, particularly in the form of artificially high frontal dunes. My study compares undeveloped and developed barrier islands of the North Carolina Outer Banks. Undeveloped shorelines illustrate the expected natural evolution of a barrier island and the developed shorelines serve as an example of a human influenced and modified barrier island. I compared both developed and undeveloped regions through quantification of island width, elevation, and overwash occurrence as a result of Hurricane Sandy in 2012. My study reveals the influence that humans have on altering barrier island states and possibly amplifying the continuation of a high relief state through overwash suppression. For the undeveloped region, overwash occurred very frequently (92.5% of study region) and although the average island width was larger (~21-47 m) than the developed region, as expected, the widths varied greatly. The minimum island widths for the developed and undeveloped areas were 197 m and 267 m, respectively, which is narrow when considering the infrastructure in the developed region. For the developed region, overwash was not expected to occur as frequently; several areas of overwash were observed (48.7% of study region), damaging critical infrastructure such as Highway 12. Island elevation results reveal that the developed region is overall higher in average elevation (~ 0.83 m) than the undeveloped region, suggesting that aeolian processes may be significant for elevation building of the back island when overwash is suppressed.