Turbidity maxima in estuarine networks: Dependence on fluvial sediment input and local deepening/narrowing with an exploratory model

An estuarine turbidity maximum (ETM) results from various subtidal sediment transport mechanisms related to, e.g., river, tides, and density gradients, which have been extensively analysed in single-channel estuaries. However, ETMs have also been found in estuaries composed of multiple interconnected tidal channels, where the water and...

Feedback Effects of Sediment Suspensions on Transport Mechanisms in an Estuarine Turbidity Maximum

The mechanisms controlling the formation of an estuarine turbidity maximum (ETM) in estuaries have been extensively investigated, but one aspect that has received much less scientific attention is the role of high suspended sediment concentrations in combination with tidal asymmetry in ETM formation. Particularly in highly turbid estuaries,...

Anthropogenic effects on the hydro-morphological development of turbid estuaries

Estuarine sediment dynamics involves estuarine hydrodynamics, sediment transport, and morphology, and strongly influence ecosystem dynamics and sustainability. In the current geological epoch, referred to as the Anthropocene, human activities are exerting increasing impacts on the environment on all scales, changing hydrodynamics, sediment...

Effects of Sediment-Induced Density Gradients on the Estuarine Turbidity Maximum in the Yangtze Estuary

An estuarine turbidity maximum (ETM) is a region of elevated suspended sediment concentration (SSC) resulting from residual transport mechanisms driven by river flow, tides, and salinity-induced density gradients (SalDG). However, in energetic and highly turbid environments such as the Yangtze Estuary, SedDG may also substantially contribute...

Regime shifts in the Changjiang (Yangtze River) Estuary: The role of concentrated benthic suspensions

Channel deepening often triggers positive feedback between tidal deformation, sediment import and drag reduction, which leads to the regime shift in estuaries from low-turbid to hyper-turbid state. In this study, a transition in profiles of suspended sediment concentration (SSC) is hypothesised by including a positive feedback loop of...

Trench Siltation near the ETM of a Well-mixed Estuary

To exploit its socio-economic functions, engineering measures are regularly applied in estuaries. Estuaries are, however, known to be very complex systems. Stemming from this complexity is the generation of a so-called estuarine turbidity maximum (ETM), which poses great siltation problems to the engineering measures. An engineering measure,...

Formation of the Zeebrugge coastal turbidity maximum: The role of uncertainty in near-bed exchange processes

Despite availability of a large amount of observational data and modelling studies, the mechanisms maintaining the Turbidity Maximum in the Belgian-Dutch coastal zone around the port of Zeebrugge (Belgium) are insufficiently understood. In order to better understand the dynamics of this turbidity maximum we examine the role of baroclinic ...

Human interventions in river-estuary systems: A case study of the Loire, France

Like many rivers around the world, the Loire river in France has a history of human interventions in order to facilitate navigation and port development. Next to affecting bed levels directly, the heavy modification of the river-estuary has induced significant changes in the hydrodynamic and morphodynamic behaviour of the Loire. As a result, the...

Three-dimensional model for estuarine turbidity maxima in tidally dominated estuaries: An idealized modeling approach

Three-Dimensional Sediment Dynamics in Well-Mixed Estuaries: Importance of the Internally Generated Overtide, Spatial Settling Lag, and Gravitational Circulation

To investigate the dominant sediment transport and trapping mechanisms, a semi-analytical three-dimensional model is developed resolving the dynamic effects of salt intrusion on sediment in well-mixed estuaries in morphodynamic equilibrium. As a study case, a schematized estuary with a converging width and a channel-shoal structure...

The influence of time dependent vertical mixing on suspended sediment in the Ems estuary

Over time, the width-averaged depth of estuaries changes due to a complex interaction of hydrodynamics and suspended sediment transport. In many estuaries one specic location with a suspended sediment concentration (SSC) higher than in the sea or in the upstream river, is found, which is called sediment<br/>trapping. The location of the maximum...

Turbidity maximum formation in a well-mixed macrotidal estuary: The role of tidal pumping

Traditionally, vertical circulation (induced by gravity circulation and tidal straining), tidal pumping, and resuspension are suggested as the major processes for the formation and maintenance of the estuarine turbidity maximum (ETM). Due to strong mixing, tidal pumping is considered as the dominating process in macrotidal estuaries. To analyze...

On sedimentation processes in a stratified estuarine system

The effect of tidal asymmetry and temporal settling lag on sediment trapping in tidal estuaries

Over decades and centuries, the mean depth of estuaries changes due to sea-level rise, land subsidence, infilling, and dredging projects. These processes produce changes in relative roughness (friction) and mixing, resulting in fundamental changes in the characteristics of the horizontal (velocity) and vertical tides (sea surface elevation) and...