Cross-shore suspended sediment transport and morphological response on a beach plain during fair weather conditions and during a storm event at The Slufter, Texel

Abstract

Cross-shore suspended sediment transports were studied at a transect over a beach plain in a small tidal inlet system The Slufter located on the barrier island Texel, The Netherlands. Field measurements of the near-bed velocity and sediment concentrations were obtained using electromagnetic current meters and optical backscatter sensors. Spectral analyses of velocity and sediment concentration was performed on two time frames of low wave conditions and two time frames of high wave conditions to reveal the contributions of waves of different frequencies to the net transport. Sediment flux measurements showed that the main contributors to the gross suspended sediment transport were made by incident waves and undertow, causing onshore and offshore transport, respectively. Co-spectral density diagrams of high wave conditions have shown a high-frequency contribution to the onshore transport, but of minor importance to the gross suspended sediment transport. Morphological change over the cross-section was mapped with a DGPS system and by using depth-of-activity rods. Swash bars were formed and slowly migrated onshore during low wave conditions and the cross-shore profile flattened during high wave events.