Author(s): E. Brand; M. Chen; A-L. Montreuil; S. Dan
Linked Author(s): Dan Song, Meng-Chen Lee, Margaret Chen
Keywords: Hydrodynamics; Intertidal zone; Sediment concentration; Backscatter intensity
Abstract: Our knowledge of suspended sediment transport in the nearshore zone is limited. This is due to difficulties in relating hydrodynamics, sediment transport and morphological changes on a meso-scale (weeks-years). The aim of this research is to study the effect of offshore suspended sediment discharge on beach morphology in relation to simultaneous measurements of hydrodynamic conditions. Hydrodynamics and suspended sediment concentrations were measured in the nearshore zone at Mariakerke, Belgium, for two months. Beach topographical profiles were measured three times during this period. Measured suspended sediment concentrations showed a clear spring-neap tidal cycle. They are not related to wave height under calm conditions (wave height< 1.0 m). The sediment concentrations were often higher during flood than during ebb tide. A small shoreward transport of sediment was observed, but the intertidal beach volume increased significantly more during the research period. Although not all morphological changes could be related to offshore sediment discharge, they could be linked to the offshore hydrodynamic conditions. When the wave steepness is small (< 0.02), the intertidal beach volume increases. Peaks in wave steepness result in erosion of the intertidal area.
Year: 2017