ABSTRACT
A 3D morphodynamic model of a meandering sand-bed river was developed using the Delft3D model package. Focus of the study was on the River Dhaleshwari, Bangladesh. The investigations focused mainly on the determination of secondary currents which are characteristic for meanders. For this purpose a boat-mounted acoustic Doppler current profiler (aDcp) at a meander bend section was used to measure the three-dimensional flow field. Model parameters were calibrated with the aDcp data for simulating primary and secondary currents. In this context the question occurred if such a calibration might lead to a good estimation of the meandering behavior of the chosen sand-bed river. To answer this question, we aimed to compare the results of one year morphodynamic computation with the field data and adopted the Brier Skill Scores (BSS) as quality parameters to assess the ability of model predictions. The model had a skill score of 0.20 and qualified as reasonable/fair according to Sutherland et al. (2004). The results of this study suggested that once properly calibrated and validated with flow measurements, the modelling approach could provide potentially a sound basis for prediction of bed level changes.
