Vulnerability Indicators for Coastal Dunes

This paper describes the development of a new parameter to characterize dune vulnerability to storm-induced erosion. Existing indicators of dune erosion vulnerability are examined, including expected cross-sectional erosion values calculated using storm characteristics. We extract a series of 110 pre- and poststorm profiles at cross-shore transects, spaced at approximately 300 m alongshore on digital terrain models of a North Carolina barrier island. Dune failure and survival are designated based on a percentage of the cross-sectional area eroded—50% or greater erosion indicates failure, less than 50% erosion, survival. Crest height does not prove to be an effective predictor of dune vulnerability. Existing cross-sectional area based parameters show some success in predicting erosion vulnerability. We improve the dune failure and survival prediction success rate using a new parameter, a surrogate moment of inertia, the erosion resistance.