Winnowing: Sub-surface entrainment of particles

This research focusses on the behaviour of fine particles which pass through the armour layer of bed material of the upper and middle reaches of a river. When the fine particles are entrained in the armour layer, it is described as ‘winnowing’ or vertical entrainment. A river bed generally consists of a coarse surface layer, which is the...

Stability of open filter structures

Granular filters are used for protection against scour and erosion. For a proper functioning it is necessary that interfaces between the filter structure, the subsoil and the water flowing above the filter structure are stable. Stability means that there is no transport of subsoil material through the filter to the water above the filter, and...

Bow Thruster Currents at Open Quay Constructions on Piles

Research into hydraulic loads by a bow thruster. The hydraulic loads on the slope at an open quay construction on piles is investigated. The propeller (bow thruster) jet induces hydraulic loads on the bed, which could result in scour holes and damage to the quay construction. Performed scale model tests provide details about the hydraulic loads...

Flexible scour protection around cylindrical piles

This research focuses on the behaviour of a granular scour protection around piles when the bed is subjected to bed degradation. Furthermore, engineering guidelines are provided to account for bed degradation in the design of the initial scour protection. To address the behaviour of the protection, a physical model is used and to obtain the...

The effect of navigation on the flow in a river trained with groynes

The study deals with the investigation of flow structures in groyne fields interacting with the flow generated by navigation. Groynes are traditionally constructed to ensure adequate water depth for navigation, so the interaction of navigation and groyne fields is nearly guaranteed. The Hungarian Danube section – which is part of the 7th...

Pumpjets in de binnenvaart

Bigger ships are replacing the small ships, also at the Amsterdam-Rijnkanaal. A direct consequence is the use of larger main propellers and increased installed engine power in order to realize acceptable ship speeds. To improve the maneuverability, the power of auxiliary bow and stern propulsion systems has increased as well. This results in...

Interaction between loaded barges and bed material

An explorative study to investigate flow velocities and sediment transport caused by the passage of a barge train over a small sandy shoal.

Integral Design of Work Channels and Basins for the Execution of Dredging Projects

During the execution of reclamation projects by Boskalis, often a temporary work channel and basin are required. This work channel is used by the dredging equipment to reach the project site as close as possible. The project site is often located in very shallow water which makes a channel necessary. The basin is used to transport the dredged...

Nieuw dwarsprofiel voor het Amsterdam-Rijnkanaal

New Profile for the Amsterdam-Rhinecanal The aim of this thesis is to design a new profile for the Amsterdam-Rhine canal. The new profile needs to be well navigable and requires to have stable bank constructions. Simultaneously several social aspects have to be taken into consideration. The assignment is summarized as follows: Design a new...

WAD een beweging; Onderzoek naar de morfologische veranderingen in het Friesche Zeegat en de gevolgen voor de bevaarbaarheid van de vaarroute naar Schiermonnikoog

Een onderzoek naar de morfologische veranderingen in het Friesche Zeegat. Na de afsluiting van de Lauwerszee is het bekken continu in verandering. Dit heeft gevolgen voor de bevaarbaarheid van de vaarroute naar Schiermonnikoog. In dit onderzoek wordt een voorspelling gedaan naar de ontwikkelingen voor het komend decennium en de gevolgen van deze...

Wave overtopping: Impact of water jets on grassed inner slope transitions

The safety of a large part of the Netherlands depends on sea dikes. Due to climate change, a sea level rise is predicted. Together with stronger storms and more wave attack, wave overtopping on the current dikes will increase. As a response, crest levels of the dikes need to be raised in order to meet the present regulations for wave overtopping...

Scour around large wooden debris: Determination of flow velocities during floods by studying local scour holes in the river Allier

Steenstabiliteit in een turbulente stroming achter een afstap

Het onderwerp van deze studie is een niet-uniforme stroming waarin sprake is van een plaatselijk verhoogde aanval op het bodemmateriaal door de lokaal hogere turbulentie. In een 15 m lange stroomgoot met een breedte van 40 cm is door middel van een backward-facing step ofwel afstap een niet-uniforme stroming gecreeerd. Om de schade aan de...

Aanslibbing Natte Strook

In scheepvaartkanalen worden er steeds meer natuurvriendelijke oevers aangelegd. Dit zijn oevers die bestaan uit een vooroever en een daarachter gelegen natte strook of plasberm. In de vooroever zitten openingen die dienen om vers water vanuit het kanaal naar de natte strook te laten stromen om ongewenste effecten van stilstaand water te...