Modeling the transport of sand and mud in the Minnesota River

Li, Chuan

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https://hdl.handle.net/2142/50722 Copy

Description

Title

Modeling the transport of sand and mud in the Minnesota River

Author(s)

Li, Chuan

Issue Date

2014-09-16

Director of Research (if dissertation) or Advisor (if thesis)

• Parker, Gary
• Viparelli, Enrica

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• River bankfull geometry
• sediment routing
• Minnesota River

Abstract

This thesis is organized into two chapters. The first chapter presents a study on the bankfull characteristics of rivers. The bankfull geometry of alluvial rivers is thought to be controlled by water and sediment supply, and characteristic sediment size. Here we demonstrate a novel finding: when bankfull shear velocity and bankfull depth are correlated against bed material grain size and bed slope, they are to first order independent of grain size and dependent on water viscosity. We demonstrate this using a similarity collapse for bankfull Shields number as a function of slope and grain size, obtained with data for 230 river reaches ranging from silt-bed to cobble-bed. Our analysis shows that bankfull Shields number increases with slope to about the half power. We show that the new relation for bankfull Shields number provides more realistic predictions for the downstream variation of bankfull characteristics of rivers than a previously used assumption of constant bankfull Shields number. The second chapter presents a study on sediment routing of the Minnesota River. We perform, via numerical modeling, an analysis of the response of the Minnesota River to changes in sediment loading. To achieve this, we developed a one-dimensional, coupled flow, sediment transport, and channel bed/floodplain morphodynamics model and derived model inputs from field parameters where possible. We show that sediment output from the system is predominantly wash load, and that changes in bed material input has little effect on sediment output in 600 years. However, changes in wash load input has a near-immediate effect on sediment output. Thus, reducing input of wash load would have greater impact on sediment yield of the Minnesota River than reducing input of bed material load.

Graduation Semester

2014-08

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http://hdl.handle.net/2142/50722

Copyright and License Information

Copyright 2014 Chuan Li

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