Sediment Sorting in Alluvial Channels
The formation of primary sedimentary structures in and along an alluvial channel occurs as a result of interactions between gravity, the physical characteristics of the sediment and fluid as well as the hydraulic environment. The occurrence of many of these structures in channels results from the presence of ripples, dunes, bars, and antidunes on the bed. However, the actual process by which recognizable structures develop arises from sorting of sediment with respect to size, shape, and density along the bed and within the stream. The settling rates of the particles, turbulent diffusion, gravitational sliding and boundary shear stress contribute to the sorting processes. From laboratory experiments, quantitative descriptions of sorting within the suspended load are presented and compared to the theoretical diffusion model. A description of the sorting processes occurring within dunes and ripples is also presented together with a discussion of some of the interactions between dunes and ripples and hydraulic roughness.
Figures & Tables
This volume contains papers presented as part of a symposium held in Toronto on May 18, 1964. These papers are mainly designed to assist the geologist, who is interested in the hydrodynamics of formation of sedimentary structures but who has little or no training in hydraulics, to become familiar with the extensive body of research which has been undertaken by hydraulic engineers interested in sediment problems.