A vortex-based model of velocity and shear stress in a partially vegetated shallow channel
Article first published online: 8 JAN 2008
Copyright 2008 by the American Geophysical Union.
Water Resources Research
Volume 44, Issue 1, January 2008
How to Cite
2008), A vortex-based model of velocity and shear stress in a partially vegetated shallow channel, Water Resour. Res., 44, W01412, doi:10.1029/2006WR005651., and (
- Issue published online: 8 JAN 2008
- Article first published online: 8 JAN 2008
- Manuscript Accepted: 22 AUG 2007
- Manuscript Received: 11 JUN 2007
- vegetated channel;
- shallow shear layer;
- coherent structures
 This paper presents a method for predicting the distributions of velocity and shear stress in shallow channels with a boundary of emergent vegetation. Experiments in a laboratory channel with model vegetation show that the velocity profile exhibits a distinct two-layer structure, consisting of a rapidly varying shear layer across the vegetation interface and a more gradual boundary layer in the main channel. In addition, coherent vortices are observed which span both layers, and are the dominant contributors to lateral momentum fluxes. From these observations, we propose a model for the vortex-induced exchange and find expressions for the width of momentum penetration into the vegetation, the velocity and shear stress at the vegetation edge, and the width of the boundary layer in the main channel. These variables, along with a momentum balance in the main channel, comprise a modeling framework which accurately reproduces the observed velocity and shear stress distributions. The predictions for the velocity and shear stress can provide a basis for modeling flood conveyance, overbank sediment transport, and scalar residence time in the vegetated layer.