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|Title:||Channel stabilization study|
|Authors:||United States. Army. Corps of Engineers. Lower Mississippi Valley Division.|
United States. Army. Corps of Engineers. Memphis District.
|Publisher:||U.S. Army Engineer Waterways Experiment Station.|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Report (Potamology Program--P-1 (U.S.)) ; 3.|
Abstract: The objective of this study was to determine, by review and analysis of prototype data and appropriate use of mathematical model, the effect of channel stabilization features on water surface profiles, channel alignment, and geometry development, and to use this information for future analysis of problem areas and design of stabilization features. The study reach selected was the Merriwether-Cherokee Reach, Mile 877 to Mile 860, on the Mississippi River. An attempt was made to establish certain hydraulic characteristics in the study reach for pre- and post-dike construction years. An effort was then made to compare these characteristics and determine if there were changes and how stabilization features contributed to these changes. Additional goals of the study were to answer questions of whether the dikes achieved their intended purpose, how long did it take for the dikes to show an effect, and has the river stabilized since the construction of the dikes. The investigation indicated certain trends concerning the effectiveness of dike systems, which are as follows: (a.) The effect of dike systems on the water surface is negligible at stages over midbank (Q=400,000 cfs). At lower flows, a 4- to 5-ft rise in stage occurred over a period of five years, then a steady decline has taken place. This decline is seen at other stations downstream and would lead one to believe the effects of the dike system have diminished and other controls have taken over. (b.) Although the overall effect of the dike systems on the Thalweg profile is one of significant beneficial depths, it can be seen that at locations where a smooth transition is not maintained a deposition problem may occur. This may result in the need for dredging at low flows. (c.) This reach indicates that the effects of dike systems on channel geometry are negligible immediately upstream or downstream of the dikes. However, channel areas opposite the dike fields have more than doubled at some sections for extreme low flow conditions. In most cases there is degradation in the channel and aggradation in the dike fields. Dikes have been successful in improving the channel, as well as the alignment. (d.) A dike field not immediately preceded by another dike field may take an extended period of time before changes are seen, with effects still being seen for some seven or eight years after construction. Dike fields following within a mile or two of another dike field begin showing changes right away and effects seem to slow significantly after three or four years. NOTE: This file is large. Allow your browser several minutes to download the file.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Potamology Investigations Report|
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