Date of Award

2016

Document Type

Open Access Thesis

Department

Civil and Environmental Engineering

Sub-Department

College of Engineering and Computing

First Advisor

Enrica Viparelli

Abstract

The Missouri River originates in the Rocky Mountains in western Montana and joins the Mississippi River near St. Louis, Missouri. Beginning in the early 1900s, engineering efforts, such as dam construction, channel narrowing, and river alignment, were performed for flood control, navigational purposes, to use of water for agricultural and industrial needs, to produce hydroelectric power and the impounded lakes for recreation. These projects permanently altered the flow and sediment transport regimes in the river and the exchange of sediment with the surrounding floodplain. We focus on the long term effects of dam construction and channel narrowing on approximately the 1400 kilometer long reach of the Missouri River from Gavins Point Dam, located near Yankton, South Dakota, and the confluence of the Missouri and Mississippi Rivers near St. Louis, Missouri. It has been shown that two downstream migrating waves, one of channel bed degradation and another of channel bed aggradation, formed in this reach in response to the changes in the flow and sediment transport regimes, sediment load, and channel geometry. Using a zeroed one dimensional morphodynamic model for large, low slope sand bed rivers we 1) predicted the magnitude and migration rate of the waves of degradation at engineering time scales, approximately 150 years into the future, and 2) quantified the changes in sand load delivered to the Mississippi River.

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