Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Civil Engineering

First Advisor

F.M. Chang


A number of dams have been constructed along alluvial rivers. These dams create reservoirs which serve to collect and store water, usually in large quantity, for use in supplying municipal needs, for supplying power and driving machinery, for furnishing irrigation, and for retaining the flow in time of floods. The characteristics of flow and the sediment-transport capacity of the channel change after these dams have been constructed. One of the major problems then confronting the hydraulic engineer is the rate of reservoir sedimentation and the change in river configuration. A problem of concern is the rapidity of reservoir sedimentation and the period of time which will elapse before the usefulness of the storage works is seriously impaired or destroyed. As the sediment deposits, the cross sectional area of the waterway is reduced. This will create the possibility of disaster due to flooding. A problem of equal concern is the damage which may take place when scouring occurs. The foundations of the existing structures in the river may be exposed and thus endanger the structures themselves. In addition to these problems, a knowledge of the future bed elevation is of importance. for the planning and optimum functioning of irrigation systems. Therefore, the change in river configuration is of prime importance, and the hydraulic engineer must continuously observe this change. The estimation of river configuration is generally based upon various methods of analytical study involving numerous related variables. Included among these variables are transport relationship for the bed materials, form of river bed [sic], and characteristics of bed materials. Often, these variables are not fully understood and have not been formulated into adequate mathematical terms for practical uses. This study is concerned with unsteady river flow in an alluvial channel. The purpose is to develop a computer solution to predict the change in riverbed elevation at transient phases.

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South Dakota State University