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|Title:||Application of channel stability methods : case studies|
|Authors:||Flood Control Channels Research Program (U.S.)|
Copeland, Ronald R.
|Publisher:||Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (U.S. Army Engineer Waterways Experiment Station) ; HL-94-11.|
Abstract: 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 sediments 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. This method is coded in the computer program SAM, "Hydraulic Design Package for Flood Control Channels." Two case studies illustrating this method are also presented here. However, simple techniques, such as the stable channel analytical method, require much more engineering judgment to apply successfully than more complex methods. A thorough knowledge of the stream is essential for a reliable stable channel analysis.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|