Characterization of the Dry Beach Profile: A Morphological Approach

Abstract

The dry part of the beach is probably the most extensively used part of the beach system. It comprises the zone from high tide level to the landward edge, which can be either a dynamic (dune field) or a fixed boundary (cliff, rocky ledge, or promenade). Here is presented a complete description of its morphology on the basis of the analysis of 91 study sites selected along the entire coast of Spain. The analysis comprises four different regions in terms of wave climate, geology, and tidal range, covering a wide range of coastal environments. In this study, a zonation of the dry beach profile is presented attending to the dynamics, the morphometric index, and the timescales of variation in which three different segments are defined: the foreshore segment, from the mean high water level to the berm, if present; the seasonal segment, which represents the zone between seasonal berms; and the interannual segment, which comprises the segment between the winter berm (or the most stable berm in case of no seasonality) and the landward edge of the beach. Besides, through cluster profile analysis-applying the K-Means classification algorithm to the entire data set of profiles-four types of dry beach profile are proposed, described, and related to a particular beach modal state: dissipative, intermediate, reflective, and ultradissipative. The observations and results presented here contribute to understanding the morphodynamics of the dry part of the beach and set the basis for subsequent studies concerning the equilibrium dry beach profile.