Keynotes Talks

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KEYNOTE RHEOMUD + FLOCMUD

Philippe Coussot, Laboratoire Navier, Université Gustave Eiffel, Champs sur Marne

Yield stress and liquefaction of muds

Muds are generally suspensions in water of colloidal particles which can form a network of (colloidal) interactions at the origin of a yield stress. Depending on the characteristics of these interactions the rheological behavior of the material may range from simple viscoplastic (steric interactions, e.g. kaolin pastes) to strongly thixotropic yield stress fluids (flocculation, e.g. bentonite suspensions) which restructure at rest but somewhat liquefy beyond the yield stress, so that the apparent behavior during flow is that of a yield stress fluid with a lower yield stress than at rest. Even more surprising behavior can be obtained in some cases, for examples a wax suspension in oil or a phosphate mud with a flocculant are brittle yield stress fluids which, when yielding, become a simple Newtonian liquid with a low apparent viscosity.

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KEYNOTE SONIMUD

Johannes M Singer, Fugro NV, Chief Scientist, Fugro Nootdorp Research Center

Mapping Harbor Basins

A fundamental question for this meeting is: “Where is what, and how can we map it quickly and efficiently?”

I would like to provide in this keynote talk an overview on techniques used for mapping Harbor basins, the seafloor and the different layers where water gradually changes to solid, and the boundaries of the harbor basin including key walls. I will attempt an overview of techniques already applied in the industry (including but not restricted to Fugro), examples and case studies from literature, as well as an outlook how more recent techniques could contribute to this. These recent techniques focus on ideas and experiments, both in TU Delft and Fugro, on using seismic techniques to map the interface layers between water, mud and solid seafloor. Tools of choice include passive and active seismic investigating interface and surface waves with a high content of shear waves probing specifically the geotechnically relevant soil and mud parameters.

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KEYNOTE 4DMUD

Andreas Malcherek, Universität der Bundeswehr, München

On the simulation of muddy waters

A conceptual approach will be presented which is able to simulate the movement of muddy waters over the full range of clear, turbulent waters to suspensions to fluid mud as well as consolidating beds. It will be shown that this approach implemented in a 1DV model is capable to reproduce the complex tidal cycle of settling, stratification and resuspension measured in the Ems estuary. 

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KEYNOTE NAUTIMUD

Mark Vantorre & Guillaume Delefortrie, Ghent University

Manoeuvring behaviour of vessels in muddy waters

The manoeuvring behaviour of vessels is highly affected by their small under keel clearance in access channels and harbours. If sedimentation and the formation of mud layers occur in these areas the manoeuvring behaviour becomes even more challenged, especially because the exact location of the bottom is not unequivocally determined. In such areas the nautical bottom definition, as stated by PIANC, should be applied. Over the past decades research at Flanders Hydraulics Research and Ghent University has been focussing on both the determination of the physical characteristics of the mud and the manoeuvring behaviour in such areas. The keynote will give an overview of this research.

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KEYNOTE 4DMUD

Andreas Wurpts, NLWKN Norden

Fluid Mud Modelling in the Ems Estuary

Lower Ems is a hyper-turbid estuary with severe ecological problems like anoxic conditions during the low discharge summer season.

In order to prepare and optimize remediation options, NLWKN Coastal Research Station has developed a coupled hydro-morphodynamical numerical model, which is capable of seamless transition between turbulent free flow and non-Newtonian fluid mud flow. The presentation covers the model description, its application to the Ems estuary, and some validation against measured data. 

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KEYNOTE BIOMUD

Justus van Beusekom, Helmholtz-Zentrum Geesthacht

Long-term SPM dynamics in the Elbe Estuary and adjacent coastal zone: 
interactions with phytoplankton underestimated?

The Elbe Estuary is experiencing manifold human induced changes including increased eutrophication, dredging activities superimposed on climate change. Based on long-term data we will show that SPM-dynamics  in the Hamburg Harbour region changed over time from background riverine levels of about 20 mg/l to up to  5-fold higher present levels observed during low freshwater discharge. These changes were paralleled by dredging activities. The source of SPM in the harbour region changed toward a dominance of marine SPM. Interactions of eutrophication-induced massive riverine phytoplankton blooms and marine SPM lead to the deposition and degradation of organic-rich material in the harbour region, now being a hotspot of among others coupled nitrification - denitrification, O₂ consumption and N₂O release. Given the importance of marine SPM in the Elbe estuary and its deposition in the Hamburg Harbour area, we will discuss the interactions between eutrophication and SPM dynamics in the coastal North Sea.