- Bed load
The term Bed load describes particles in a flowing fluid (usually a river) that are transported along the bed. This is in opposition to
suspended load andwash load which are carried entirely in suspension.Bedload moves by a variety of methods, including rolling, sliding,
traction , andsaltation .Generally, bed load downstream will be smaller and more rounded than bed load upstream (a process known as
downstream fining ). This is due in part toattrition andabrasion which cause the stones to bump against each other and against the river channel, thus removing its rough texture and making it smaller. However,selective transport of sediments also plays a role in relation to downstream fining: larger-than average particles are more easilyentrained than small-than average particles, since larger particles are protruding from the bed whereas small particles are shielded/ hidden by larger particles thus requiring a higher lift and drag force to entrain.References
*Waugh, D. "The New Wider World", Cheltenham: Nelson Thorns Ltd, 2003.
*Ashworth, P.J and Ferguson, R.I (1989) Size-selective entrainment of Bed Load in Gravel Bed Streams, "'Water Resources Research", Vol 25 (4): 627-634
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