Estimating the Vulnerability of a Sandy Coast to Storm-Induced Erosion

Abstract

A criterion or index for assessing the hazard of storm-induced coastal erosion is suggested. It is based on comparison of actual beach volume $$~{{V}_{b}}$$ and its optimal value $${{V}_{{b^{*}}}}$$ sufficient to avoid irreversible beach changes due to severest storm attack over the year. The erosion hazard level is determined taking into account the difference of $$~{{V}_{b}}$$ and $${{V}_{{b^{*}}}}$$ ; it reaches the maximum (3 points) when the actual beach volume becomes less than a half the optimal value (0 points corresponds to $$~{{V}_{b}}$$ > $${{V}_{{b^{*}}}}$$ ). To calculate the erosion index, a representative beach profile is required, as well as the data on the mean sand size and wind/wave regime. The erosion index is tested on the coasts of the Anapa bay-bar (Black Sea) and southern part of the Vistula Spit (Baltic Sea). The index makes it possible distinguish vulnerable sections of the coast, and at the same time it reflects the sediment deficit volume that could be used in shore protection designs.