On bed particle diffusion in gravel bed flows under weak bed load transport
Article first published online: 25 JUN 2002
Copyright 2002 by the American Geophysical Union.
Water Resources Research
Volume 38, Issue 6, pages 17-1–17-9, June 2002
How to Cite
On bed particle diffusion in gravel bed flows under weak bed load transport, Water Resour. Res., 38(6), doi:10.1029/2001WR000513, 2002., , , and ,
- Issue published online: 25 JUN 2002
- Article first published online: 25 JUN 2002
- Manuscript Revised: 3 DEC 2001
- Manuscript Accepted: 3 DEC 2001
- Manuscript Received: 14 MAR 2001
- bed load;
- gravel bed rivers;
- particle diffusion
 We introduce a new conceptual model for longitudinal and transverse diffusion of moving bed particles under weak bed load transport. For both rolling/sliding and saltating modes the model suggests that the particle motion is diffusive and comprises at least three ranges of temporal and spatial scales with different diffusion regimes: (1) the local range (ballistic diffusion), (2) the intermediate range (normal or anomalous diffusion), and (3) the global range (subdiffusion). The local range corresponds to ballistic particle trajectories between two successive collisions with the static bed particles. The intermediate range corresponds to particle trajectories between two successive periods of rest. These trajectories consist of many local trajectories and may include tens or hundreds of collisions with the bed. The global range of scales corresponds to particle trajectories consisting of many intermediate trajectories, just as intermediate trajectories consist of many local trajectories. Our data from the Balmoral Canal (the intermediate range) and Drake et al.'s  data from the Duck Creek (the global range) provide strong support for this conceptual model and identify anomalous diffusion regimes for the intermediate range (superdiffusion) and the global range (subdiffusion).