Headland sand bypassing - Quantification of net sediment transport in embayed beaches, Santa Catarina Island North Shore, Southern Brazil

This paper presents a comprehensive study of headland bypassing around seven headlands with different orientations and degrees of wave and tide-induced current exposure, located on the northern shore of Santa Catarina island, southern Brazil. It encompasses an extensive dataset including detailed in situ measurements of bathymetry, beach profiles, sediment transport (traps), waves, currents and tides. The entrained sediment decreased in magnitude towards the more sheltered coast while maintaining comparable sediment grain distributions, supporting the hypothesis of a connection between beaches. Based on in situ measurements, a numerical model was calibrated (waves, currents and tides) and validated, with errors representing 11% of the magnitude of the measurements. Furthermore, three sediment transport formulae were tested to identify the one that best reproduced the processes at the study site. A model using tides, winds and full wave spectra as input was run to identify the general (net) trend of annual sediment transport in the study area aiming to identify if/where headland bypassing occurs. The results show that headland sand bypassing does occur in the study area confirming the anticlockwise sediment transport pathway. The present work highlights the role of sediment bypassing on embayed-headland bound beaches, which are usually considered to be closed cells.