Date of Award

1-1-2013

Document Type

Open Access Dissertation

Department

Civil and Environmental Engineering

First Advisor

M. Hanif Chaudhry

Abstract

Steady flow at a breached levee is studied in this dissertation through a generalized model and a case study. The generalized experimental set-up consists of a main channel with an opening in its side wall and an adjustable sluice gate at its downstream end. Water surface elevation and the three-dimensional velocity field are measured by a point gauge and an Acoustic Doppler Velocimeter (ADV), respectively. Time-averaged measured values of velocity field and free surface elevation are presented. In addition, Froude Number, turbulent kinetic energy (TKE) and bed shear stress are computed from the measured results. Results show that the flow is one-dimensional near the inlet and outlet of the main channel. However, it is three-dimensional near the breach. There is a zone of depression having dimensions less than the breach length near the breach in the surface profile. The Froude Number indicates the flow is critical near the breach. The bed shear stress shows that the breach area is prone to erosion. A generalized analytical model is developed to predict the approximate flow depth and velocity at the breach by knowing the flow depths at inlet and outlet, discharge at inlet, channel widths and breach length. The 17th Street Canal breach is employed as a case study. Detailed measurements of the

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