Tidal asymmetry and residual sediment transport in estuaries

Theoretical study on tidal asymmetry and application to the Westerschelde estuary.

Fine sediment transport near coral reefs islands in the Singapore Strait

The objective of this study is to determine large scale of fine sediment transport near coral reefs islands in the Singapore Strait. Coral reefs in the Singapore Strait face great pressure due to high sedimentation and turbidity, which cause decreasing of light penetration and of environment quality for the coral growth. Sedimentation and high...

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...

Fine sediment transport by tidal asymmetry in the high-concentrated Ems River: Indications for a regime shift in response to channel deepening

This paper describes an analysis of the observed up-river transport of fine sediments in the Ems River, Germany/Netherlands, using a 1DV POINT MODEL, accounting for turbulence-induced flocculation and sediment-induced buoyancy destruction. From this analysis, it is inferred that the net up-river transport is mainly due to an asymmetry in...

Edge scour around an offshore wind turbine

Wind energy has experienced an enormous growth in the last years and is becoming more and more popular as an alternative for conventional power. Large growth numbers are also expected for the coming years, for onshore as well as for offshore wind energy. Currently, a wind power capacity of almost 4 GW is installed offshore in the European Union,...

Assessment of the effects of the Zuider Sea closure on the hydrodynamics of the Wadden Sea inlets

Large hydrodynamic and morphodynamic changes have taken place in the western Dutch Wadden Sea due to the closure of the Zuider Sea in the early 1930s. Hydrodynamic simulations for three situations, viz. just before the closure, just after the closure and at present, have been carried out in order to investigate the hydrodynamic changes since the...

The future of the Oosterschelde with a new inlet channel

After the storm surge of 1953, the Dutch Delta project was initiated in order to protect the southwestern part of The Netherlands. A storm surge barrier in front of the Oosterschelde and various dams at the back of the estuary were constructed. These interventions led to a large change of the hydrodynamics of the Oosterschelde: a large decrease...

Impact of estuarine convergence on residual circulation in tidally energetic estuaries and inlets

Estuarine convergence (landward reduction of width and/or depth) is known to have the potential to significantly enhance estuarine circulation, a result theoretically derived under the assumption of constant eddy viscosity. Recent studies of longitudinally uniform energetic tidal channels indicate that tidal straining, a process driven by...

Modeling estuarine morphodynamics under combined river and tidal forcing

Estuarine morphodynamics are of broad importance to estuaries’ functions related to navigation, human settlement and ecosystems. Inspired by the Yangtze River estuary (YRE), this study aims to explore the impact of river discharge, tides and their interaction on long-term estuarine morphodynamics. Use is made of 1D and 2D process-based models....

Fine sediment transport into the hyperturbid lower Ems River: The role of channel deepening and sediment-induced drag reduction

Deepening of estuarine tidal channels often leads to tidal amplification and increasing fine sediment import. Increasing fine sediment import, in turn, may lower the hydraulic drag (due to a smoother muddy bed and/or sediment-induced damping of turbulence), and therefore, further strengthen tidal amplification, setting in motion a process in...

Semi-nonlinear analysis of the effect of deepening on tidal asymmetry

In the last century, various tidal rivers in Europe have seen a large tidal amplication, which is believed to be caused by the deepening and channelization of these rivers. Additionally, large increases in suspended sediment concentrations induced by flood dominance are thought to have decreased the effective hydraulic drag, enhancing further...

Net sediment transport by tidal asymmetry in the hyper-turbid Ems River

On the stability relations between tidal asymmetry and morphologies of tidal basins and estuaries

Simple stability relationships are practically useful to provide a rapid assessment of coastal and estuarine landforms in response to human interventions and long‐term climate change. In this contribution, we review a variety of simple stability relationships which are based on the analysis of tidal asymmetry (shortened to “TA”). Most of the...

Quantification of Tidal Asymmetry and Its Nonstationary Variations

Tidal wave deformation and tidal asymmetry widely occur in tidal estuaries and lagoons. Tidal asymmetry has been intensively studied because of its controlling role on residual sediment transport and large‐scale morphological evolution. There are several methods available to characterize tidal asymmetry prompting the need for an overview of...

Tidal control in the Lower Ems: An indicative study into the effects of controlled barrier operation on the tidal asymmetry in the Lower Ems river

The lower Ems river suffers from hyper-turbid conditions. These conditions are caused by channel deepening over the last 50 years, resulting in an asymmetrical tidal wave. This asymmetry has resulted in an increased<br/>import of sediment into the Ems river. Recently some effort has gone into determining whether or not the local tidal barrier ...

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,...