Nearshore sediment transport processes due to moderate hydrodynamic conditions

Abstract On the beach of the island of Norderney sedimentological, morphological and hydrodynamic measurements have been carried out in order to investigate sediment transport processes in the course of a tidal cycle which was characterized by moderate hydrodynamic conditions. Wave heights varied between 0.3 and 0.5 m. An area of 90 m2 within a groyne field was surveyed. Sediments samples were taken on a 5 m grid at low tide. Sediment flux was determined at each sampling site by means of depth-of-activity rods. The grain size distributions of the sediment samples were determined by dry sieving. Under the prevailing hydrodynamic conditions a landward sediment transport was observed. The mainly negative sediment budget in the seaward section and the landward directed distribution of fluorescent sediment tracers suggest a dominant onshore transport during the investigated tidal cycle. This is also reflected in the changes observed in sediment textures.