The Effect of Intertidal Areas on The Residual Transport and Sediment Accumulation

Estuarine Turbidity Maxima (ETM) refer to regions within estuaries where sediment concentration is elevated due to converging sediment transport mechanisms. Typically, an ETM is found near the tip of the salt wedge, but in tide-dominated systems, it may be transported further up-estuary by tide-induced processes up to the tidal limit. Additionally, fluid mud has been observed many kilometers landwards of the salt intrusion limit. Although the Ems Estuary in the Wadden Sea has been extensively studied, up-estuary transport mechanisms remain poorly understood. Numerical modelling is frequently used to investigate the landward transport of sediment, which is likely driven by a combination of factors such as sediment-induced density currents, tidal asymmetry, lag effects, and sediment trapping in the fluid mud layer. This process has been linked to gravitational circulation. However, existing baroclinic sediment transport models fail to reproduce the strong up-estuary transport observed, indicating that depth-average analysis is insufficient to understand the process in detail. Furthermore, limitations in data collection in the deepest parts of the channel also limit understanding. This project focuses on the near-bed part of channels and aims to improve understanding of up-estuary transport and how highly modified estuaries transport particles upstream. The project also seeks to determine the extent to which 3D estuarine circulation contributes to sediment trapping. Ultimately, a 3D model will be developed for the Fairway to Emden to obtain quantitative insights into hydrodynamics and sediment dynamics.