Modelling the effect of time-dependent river dune evolution on bed roughness and stage
Article first published online: 15 OCT 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Earth Surface Processes and Landforms
Volume 35, Issue 15, pages 1854–1866, December 2010
How to Cite
Paarlberg, A. J., Dohmen-Janssen, C. M., Hulscher, S. J. M. H., Termes, P. and Schielen, R. (2010), Modelling the effect of time-dependent river dune evolution on bed roughness and stage. Earth Surf. Process. Landforms, 35: 1854–1866. doi: 10.1002/esp.2074
- Issue published online: 1 DEC 2010
- Article first published online: 15 OCT 2010
- Manuscript Accepted: 12 JUL 2010
- Manuscript Revised: 6 JUL 2010
- Manuscript Received: 7 DEC 2008
- river dunes;
- hydraulic roughness;
This paper presents an approach to incorporate time-dependent dune evolution in the determination of bed roughness coefficients applied in hydraulic models. Dune roughness is calculated by using the process-based dune evolution model of Paarlberg et al. (2009) and the empirical dune roughness predictor of Van Rijn (1984). The approach is illustrated by applying it to a river of simple geometry in the 1-D hydraulic model SOBEK for two different flood wave shapes. Calculated dune heights clearly show a dependency on rate of change in discharge with time: dunes grow to larger heights for a flood wave with a smaller rate of change. Bed roughness coefficients computed using the new approach can be up to 10% higher than roughness coefficients based on calibration, with the largest differences at low flows. As a result of this larger bed roughness, computed water depths can be up to 15% larger at low flow. The new approach helps to reduce uncertainties in bed roughness coefficients of flow models, especially for river systems with strong variations in discharge with time. Copyright © 2010 John Wiley & Sons, Ltd.