Thermally destratifying lakes against blue algae with rising air bubbles

Mixing systems are used in deep lakes to prevent blue algae from rapidly growing. Air bubbles rise from the bed, dragging water from below upwards. The resulting vertical circulation suppresses blue algae growth. However, these systems demand electricity of about €25,000 per km2 per year. The airlift promises to mix the water more efficiently,...

Morphological development after the July 2014 flow slide on the tidal flat of Walsoorden in the Western Scheldt

The overall behaviour of the tide-dominated Western Scheldt is in general well known. Its multichannel-system consists of ebb and flood channels, separated by intertidal areas; the tidal flats. The estuary shows a dynamic behaviour of erosion and sedimentation of the tidal flats. A large flow slide occurred at the tidal flat of Walsoorden in...

Modelling sand-mud-bed interaction in the Scheldt estuary

The tide-dominated Scheldt estuary is located in the southwest of the Netherlands. From the Dutch-Belgian border seawards, it consists of a system of channels and shoals and an ebb-tidal delta facing the North Sea. The behaviour of non-cohesive (sand) and cohesive (mud) sediment particles in the area are (until now) generally studied using...

Modelling the impact of large scale sediment dumping on the meso-scale hydro- and morphodynamics in the Western Scheldt

The current report aims to understand the hydro- and morphodynamic response of the Western Scheldt in a large sediment dumping operation. This study investigates the estuary’s response to sediment dumping in the Everingen channel area, which is located in the middle of the Scheldt Estuary, The Netherlands. Furthermore, it studies whether these...

Turbidity Currents in Reservoirs

Turbidity currents are major transport agents in reservoirs in which high concentrations of fine sediments flow in. Reservoir sedimentation due to turbidity currents is often severe in these cases. Turbidity currents are not well understood due to their complex turbulent flow structure, the interaction between the flow with the particles and the...

Impact of beach states on net longshore sediment transport

The response of longshore sediment transport to the morphodynamic state of the beach was assessed with the use of the process based numerical model, Delft 3D. For this purpose, idealized simulation bathymetries that reflect morphological characteristics of two different beach states (namely longshore bar and trough and transverse bar and rip)...

Impact Assessment of the Rhine ROFI on the Annual Cross-shore Sand Transport

Using D-Flow Flexible Mesh numerical software to simulate the region of freshwater influence of the Rhine in front of the Dutch coast to assess the influence of stratification on the near-bottom velocities and the related cross shore sand transport.

The effect of islands in the Río Magdalena on discharge and sediment transport into the Canal del Dique, Colombia

Controlling the distribution of water and sediment at river bifurcations is one of the main challenges in river engineering and management. This distribution affects the stability of river bifurcations as well as the distribution of flooding risk, navigability and environmental conditions. The governing factors are the hydrodynamics of the two...

An assessment on hydro- and morphodynamic proceses at the sand motor during the Decemberstorm of 2013

In 2011 the Sand Motor was realised at the coast of the province of South-Holland as a pilot project combining different functions such as safety, recreation and nature development, following the philosophy of Building with Nature. The idea was to create a mega nourishment that would supply the coastal system between Hook of Holland and...

Ecosystem-based port design: An approach for sustainable port development

The world population is growing. Together with the population, the need for resources is growing, as is the need for the transportation of these resources. A significant part is carried out through marine transport, directly relating to the increasing need for port development. All over the world, a shift increasingly occurs towards applying...

Modelling of Grain Sorting Mechanisms in the Nearshore Area for Natural and Nourished Beaches

In this study a modelling approach was investigated that takes into account the effect of short wave grouping on long wave motions, calculating sediment transport and morphology with multiple fractions and a layered bed stratigraphy. After extensive testing and validating this model using data collected in a wave flume in Hannover this model was...