Effects of Tidal Stage on the Wave Climate Inshore of a Sandbank

Abstract

Coughlan, C., Vincent, C.E., Dolphin, T.J. and Rees, J.M., 2007. Effects of tidal stage on the wave climate inshore of a sandbank. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 751 – 756. Gold Coast, Australia, ISSN 0749.0208 Modelling of the processes that link the movements of offshore sandbanks to erosion and accretion of neighbouring beaches was undertaken to improve understanding of the links between sandbanks and beaches in order to inform coastal management. The effect of varying tidal stage on the wave climate inshore of a sandbank was examined using the TELEMAC suite of numerical models. Longshore sediment transport was calculated using the CERC formula to investigate changes to the magnitude and pattern of coastal erosion/accretion according to tidal stage using waves from two of the most frequent directions. Tidal stage has a significant impact on the inshore wave climate, varying wave heights by up to 0.5 m and increasing tenfold the magnitude of the longshore sediment transport. Tidal elevation appears to play a more important role than the tidal currents, with wave heights and longshore sediment transport maximum at high water. The pattern of alongshore erosion and accretion varies more strongly with wave direction than tidal stage.