Application of Channel Stability Methods - Case Studies
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS LAB
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The analytical method presented herein, developed through the Flood Control Channels Research Program, is intended for use to estimate channel dimensions for preliminary design studies. It accounts for the movement of sediment and for varying roughness due to changing bed forms. It also attempts to account for the effects of bank roughness that can be significant in small channels and is essentially neglected in many approaches that assume wide channels. This analytical approach determines dependent design variables of width, slope, and depth from the independent variables of discharge, sediment inflow, and bed material composition. It is especially applicable to small streams because it accounts for transporting the bed material sediment discharge in the water above the bed, not the banks, and because it separates total hydraulic roughness into bed and bank components. A stability analysis can be done by first determining the bed material sediment load entering the project reach, and then analyzing the family of slope-width solutions that satisfy the resistance and sediment transport equations. The resulting stability curve provides many combinations of slope and base width, all of which will be stable for the prescribed channel design discharge. Combinations of width and slope that plot above the stability curve will result in degradation, and combinations below the curve will result in aggradation. The greater the distance from the curve, the more severe the instability. Alluvial streams, Sedimentation, Flood- control channels, Stability analysis, Sediment transport, Stable channels.
- Hydrology, Limnology and Potamology
- Civil Engineering