Abstract:
The main objective of this study is to investigate the effect of sediment flushing on the morphology of
artificially embayed beaches using field data and numerical modelling. The sandy stretch of Cova-Gala in the
West Coast of Portugal, characterized by a high-energy wave climate, is critical regarding erosion-flooding
risks. The site was monitored from August 2018 to February 2019, including the wave climate, the sea level
and the beach topo-bathymetric elevation via sonar-single beam, GNSS-RTK and drone surveys. During this
period several erosive events caused the retreat and lowering of the upper beach profile. The XBeach model
was applied to simulate the morphological evolution during the monitored period using synoptic wave and sea
level data as the hydrodynamic forcing. The results of the data-model analysis reveal that i) the alongshore
extension of the sedimentological cells and the cross-shore structures length have a relevant influence on the
lee-side erosion patterns, which affect the overall surrounding morphology, ii) the model overestimates the
scouring of the seawall toe, particularly with the 1D mode; and iii) the beach backshore typology, dune and
seawall, has a great influence on beach dynamic processes.
