Submitted to: Trans American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 1998
Publication Date: N/A
Technical Abstract: Accurate prediction of suspended sediment transport remains a critically important problem in stream hydrology and hydraulics for the assessment of engineering practices, anthropogenic impacts, and landscape evolution. Herein we describe an alternate approach to predict the vertical diffusion and distribution of suspended sediment in rivers and streams given easily obtained flow and sediment data. The approach described is initially limited to sediment transport over nominally flat beds where the turbulent flow domain is homogeneous, unencumbered by flow separation and the formation of coherent structures associated beds covered with ripples and dunes. Experimental data collected using phase Doppler anemometry quantified the turbulent motions of sediment particles, grain size, and suspended sediment concentration as well as the turbulence characteristics of the flow over upper-stage plane beds. These measurements and data from past investigators were used to characterize the effects of particle size and density on the distribution of suspended sediment using the model presented by Shao and Xia (1991). In this model, equations were derived describing the vertical diffusion and concentration distribution of sediment from the fundamental equations governing the motion of discrete solid particles in a turbulent flow. It will be shown that reasonable inference can be made regarding the influence of particle size and density on vertical diffusion of suspended sediment. This development is intended to provide better characterization of potential transport capacity of suspended sediment mixtures in rivers and streams.