Narrow Results

There is a general lack of knowledge of combined cross-shore and longshore changes in gravel barrier beach morphology due to storms. A cluster analysis followed by a multidimensional scaling ordination revealed that the storms affecting a gravel barrier in the southwest of England (Slapton Sands) fall into two very distinct groups: easterlies with mainly wind waves, and southerlies dominated by swell. The morphological response of the barrier to these two typical storm conditions was found to be opposite. Easterly storms induce upper beach erosion and lower beach accretion, while southerly storms cause upper beach accretion and lower beach erosion. In addition, the net alongshore sediment transport for southerlies is northward, while for easterlies it is southward. Video-derived shorelines over three years indicate that the barrier has rotated significantly, as demonstrated by widening of the northern end, and narrowing of the middle section. It is argued that the rotation is caused by a recent change in dominance of one storm type over the other.