Sediment Reworking on Sandy Beaches

Abstract

A sandy beach is actually a prism of sediment, as shown in Figure 1. The prism is subjected to reworking at various time scales; if it were otherwise, the sandy beach would evolve into a stable vegetated land form. Under the impact of extreme events, the prism is subject to extension at the landward limit to include the incipient foredune (which is usually colonized by sand tolerant pioneer species), and more rarely the established frontal dune, and at the seaward limit to include the zone which is normally stable enough to be subject to bioturbation. The sandy beach thus includes far more than the recreational, or subaerial, beach which is merely the berm and swash zone, a very small proportion of the total sandy prism. The sandy beach is subject to reworking by aeolian, biological and hydraulic processes, but principally the latter.