MEDIUM-TERM MORPHODYNAMIC MODELING OF MIXED MUD AND SAND IN THE

Markus Witting, Christof Wehmeyer, Hanz Dieter Niemeyer

Abstract


A morphodynamic model for the Jadebusen basin based on the current DELFT3D model is established. With
morphological information such as qualitative measurements of SPM-concentration (Suspended Particular Matter) and
bottom change estimates as well as detailed surveys of a sand pit refilling process the model parameters for cohesive
transport (Partheniades 1965) are calibrated. Within a period of 8 month, which is condensed to a representative
period of 28 days for the modeling, almost 45% of the initial pit volume was refilled with mud. Despite the lack of
specific field measurements a setup of mud transport parameters can be defined, which allows further investigations of
sand pit locations in the Jadebusen basin. On major outcome is that critical erosion shear stresses for mud should be
spatially varied in order to account for the different consolidation states of the mud fraction. Furthermore the paper
addresses the problem of the initial grain size distribution for graded sediment transport. Wadden flat types are
characterized based on aerial observations which build the underlying information for a relocation model run.

Keywords


morphodynmic modeling; cohesive sediment transport; initial grain size distribution

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