Lagrangian sediment transport modelling as a tool for investigating Coastal connectivity

Estuaries and coasts can be conceptualized as connected networks of water and sediment fluxes. These dynamic geomorphic systems are governed by waves, tides, wind, and river input, and evolve according to complex nonlinear transport processes. To predict their evolution, we need to better understand the pathways that sediment takes from source...

Simultaneous measurements of tidal straining and advection at two parallel transects far downstream in the Rhine ROFI

This study identifies and unravels the processes that lead to stratification and destratification in the far field of a Region of Freshwater Influence (ROFI). We present measurements that are novel for two reasons: (1) measurements were carried out with two vessels that sailed simultaneously over two cross-shore transects; (2) the measurements...

Do intertidal flats ever reach equilibrium?

Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the basic processes and feedback mechanisms underlying...

A finite volume approach for shallow water flow accounting for high-resolution bathymetry and roughness data

This study presents a finite volume hydrodynamic model for shallow water flow that computes on a coarse grid, but accounts for high-resolution bathymetry and roughness variations on a subgrid. The detailed information can be incorporated by using the assumption of a uniform flow direction and a uniform friction slope within a part of a coarse...

Temporal bed level variations in the Yangtze tidal flats (abstract)

The Yangtze River is one of the largest rivers in the world and the longest one in Asia. Its estuary forms an important entrance for shipping, but is also a key ecological system. Especially the inter-tidal flats are valuable habitats. The health and integrity of the estuarine tidal flat are however under pressure due to anthropogenic influences...

Evolution of the Yangtze Tidal Flats: A One-Dimensional Approach (abstract)

The Yangtze river (China) is one of the biggest rivers in the world in terms of length, area, discharge and sediment load. The large sediment supply by the Yangtze river resulted in the development of large coastal wetlands in its estuary, which form rich and important ecosystems. Human activities are increasingly influencing the Yangtze estuary...

Observations and modeling of steep-beach grain-size variability

Novel observations of surface grain-size distributions are used in combination with intra-wave modeling to examine the processes responsible for the sorting of sediment grains on a relatively steep beach (slope?=?1:7.5). The field observations of the mean grain size collected with a digital camera system at consecutive low and high tides for a 2...

A conceptual framework for shear flow–induced erosion of soft cohesive sediment beds

This paper proposes a conceptual framework for erosion of cohesive sediment beds. We focus on cohesive beds, distinguishing between floc erosion, surface erosion, and mass erosion. By (our) definition, surface erosion is a drained soil mechanical process, whereas mass erosion occurs under undrained conditions. The eroding shear stress is modeled...

Simulating the large-scale spatial sand-mud distribution in a schematized process-based tidal inlet system model

Tidal basins, as found in the Dutch Wadden Sea, are characterized by strong spatial variations in bathymetry and sediment distribution. In this contribution, the aim is at simulating the spatial sand-mud distribution of a tidal basin. Predicting this spatial distribution is however complicated, due to the non-linear interactions between tides,...

Development of tidal watersheds in the Wadden Sea

The Wadden Sea consists of a series of tidal lagoons which are connected to the North Sea by tidal inlets. Boundaries to each lagoon are the mainland coast, the barrier islands on both sides of the tidal inlet, and the tidal watersheds behind the two barrier islands. Behind each Wadden Island there is a tidal watershed separating two adjacent...

River Engineering

In this syllabus an overview is given of the basic knowledge, which is required to prepare interventions in rivers and to estimate the consequences of these interventions. The utilization of the river for human purposes and the knowledge of hydraulics, sediment transport and morphology will be treated. At the end of this syllabus some practice...

Rivierwaterbouwkunde

Deze syllabus beoogt een overzicht te geven van de basiskennis die nodig is om ingrepen in de rivier voor te bereiden en de gevolgen ervan te kunnen inschatten. Er wordt ingegaan op het gebruik dat de mens maakt van de rivier en op de kennis van de hydraulica, het sedimenttransport en de morfologie. Aan het einde van het dictaat worden...

A stochastic formulation for erosion of cohesive sediments

The linear formulation for erosion E = M(?b??c), often applied in engineering applications, has two properties, which do not always comply with field and laboratory observations, they are as follows: (1) The erosion rate is zero below the critical bed shear stress ?c and increases linearly with bed shear stress ?b, when exceeding the critical...

The Relevance of a Back-Scatter Model for Depth-Averaged Flow Simulation

This study demonstrates the importance of a sophisticated sub-grid model when performing a depth-averaged unsteady RANS simulation of a shallow flow. The reduction of resolution and the spatial dimensions exclude important physical processes as present in three-dimensional turbulence. Especially the effect of the bottom turbulence on the...

Shallow mixing layers, Ondiepe menglagen

A linear approach for the evolution of coherent structures in shallow mixing layers

The development of large coherent structures in a shallow mixing layer is analyzed. The results are validated with experimental data obtained from particle tracking velocimetry. The mean flow field is modeled using the self-similarity of the velocity profiles. The characteristic features of the down-stream development of a shallow mixing layer...

Grootschalige horizontale structuren in een rivier met uiterwaarden: Een experimentele studie

Dit afstudeerwerk bestaat uit het ontwerpen van een fysisch model, het uitvoeren van experimenten, het verwerken van de metingen en het interpreteren van de resultaten. Allereerst wordt in hoofdstuk 2 aan de hand van een probleemanalyse ingegaan op de literatuur betreffende de (ondiepe) menglaagstroming en wordt de doelstelling van het...