Surfzone-beach-dune interactions along a variable low wave energy dissipative beach

Abstract

The different possible factors that influence or drive the observed volumetric and morphological variation in foredunes located along 16 km of a low wave energy, dissipative southern section of the 190 km long Younghusband Peninsula (South Australia) are examined. Grain size, wind energy, coastline orientation, and vegetation species presence/absence vary only slightly along this coast providing a unique site to study other drivers of coastal change. Results show that foredune height and volume progressively increase towards the north coincident with a gradual increase in wave energy. A significant correlation between foredune volume and wave energy is established, while no apparent relationship with other controlling factors was found, confirming the importance of wave energy in the dune building process on wave-dominated beaches. Results indicate that (1) all other factors being equal, wave energy can drive the morphological evolution of foredunes; (2) minor changes in wave energy can result in differences in the long-term beach and dune sediment budget; and, (3) the surfzone-beach-dune interactions model is applicable to coasts with small scale gradients in wave energy.