Erosion, Sedimentation, and Geomorphology
On gravel-bed roughness characterization
Article first published online: 9 JUL 2010
Copyright 1998 by the American Geophysical Union.
Water Resources Research
Volume 34, Issue 3, pages 517–527, March 1998
How to Cite
1998), On gravel-bed roughness characterization, Water Resour. Res., 34(3), 517–527, doi:10.1029/97WR02886., , and (
- Issue published online: 9 JUL 2010
- Article first published online: 9 JUL 2010
- Manuscript Accepted: 9 OCT 1997
- Manuscript Received: 28 JAN 1997
The random field approach for gravel-bed roughness characterization, which is based on the presentation of bed elevations as a three-dimensional random field, is justified as an alternative to the characteristic particle size approach. We first show that the bed elevation distribution is close to Gaussian and then investigate gravel-bed roughness using the second-order structure function. The latter reveals two distinct regions: a scaling region at small spatial lags and a saturation region at large scales. The scaling exponent H (a form of Hurst exponent) appears to be isotropic and universal for both manually created “unworked” gravel beds (H=0.5) and natural water-worked gravel beds (H=0.79). However, the gravel-bed roughness, in general, is not isotropic and should be characterized by three independent characteristic scales. A simple model of gravel-bed roughness based on the structure function parameterization is developed and compared with the characteristic particle size approach.