Author(s): Jord J. Warmink; Ralph M. J. Schielen

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Keywords: Flood management; Hydrodynamic modelling; Bed forms; Time-lag approach; Hydraulic Roughness

Abstract: Accurate forecasts of water levels are essential for flood protection management. The hydraulic roughness of the river bed is dominated by bed forms. Under flood conditions the river bed is highly dynamic; bed forms grow and decay as a result of the changing flow conditions, thereby influencing the roughness. Hydrodynamic models are applied to predict water levels using the hydraulic roughness of the river bed as a calibration coefficient. The objective of this study is to predict the bed form dimensions during a discharge wave to improve roughness prediction and associated water levels. We showed that the time-lag approach gives reliable predictions of bed form dimensions for a discharge wave in a flume. We coupled the time-lag approach to the hydrodynamic model Sobek, to enable a physically-based prediction of water levels during a discharge wave without the need for calibration.

DOI:

Year: 2014