The relation between longshore variations in grain size distribution and sediment transport processes

Abstract

This study investigates the relationship between grain-size distributions and sediment transport processes at Ängelholm Beach in southwest Sweden. In total, 308 longshore and cross-shore distributed sediment samples are analysed with respect to median grain size and sorting. The longshore sediment transport is almost unidirectional from north to south. Its gradients cause erosion in the north and accretion in the south. The longshore transport sorts the sediment, leading to coarsening in eroding areas and deposition of finer sediment in accreting areas. In the eroding part of the beach, the aeolian transport is limited, and the median grain sizes on the beach are coarser than in the dunes. In the accreting part of the beach, where the dunes are prograding, sediment within the range of dune-building grain-sizes is mostly available at the beach. The results support that sediment supply of appropriate grain sizes is an important factor controlling the long-term dune evolution