Morphologic change and morphodynamics at high-energy embayed beaches in Southwestern Portugal

Abstract

Along the southwestern coast of Portugal, a high-energy, swell dominated environment with a markedly seasonal wave climate, morphologic change in three embayed beaches was regularly monitored over a two year period. While a general seasonal pattern was identified, the occurrence of a storm group induced dramatic beach response, producing marked interannual variability. Significant spatial variations in behaviour emerged during the monitoring period, inducing alongshore non-uniform beach change within each embayment. Megarips were the prevailing mechanism responsible for the extreme erosion experienced in all three beaches, and their specific location (controlled by topography) contributes to the variability observed within each beach. Despite severe beach erosion, dunes were unaffected, which suggests long-term stability of these high-energy, dissipative, embayed coastlines.