Lag-driven sediment transport in tidal basins : an Eulerian perspective

As tidal flats have to keep pace with sea-level rise and withstand human interferences, it is crucial to quantify the transport mechanisms underlying sediment dynamics. The lag effects (LEF - e.g. settling and scour lag) are barotropic mechanisms of suspended transport related to tidal propagation and regarded to be among the main drivers of landward SPM accumulation. Their classic descriptions are in a Lagrangian frame and do not account for wind waves. These restrictions need to be overcome, as: 1) diffusive processes and other barotropic mechanisms (tidal asymmetry - TAS, Stokes’ drift compensation - SDC) are defined in an Eulerian frame and therefore cannot be compared with LEF ; 2) waves dominate resuspension in the intertidal zone. The study aims at quantifying the relative contributions of LEF, TAS and SDC on the residual fluxes of non-cohesive fine sediment, by means of a fully Eulerian framework comprising short wind waves. We consider the Vlie basin as test case.