Water Surface Profiles in Compound Channel with Multiple Critical Depths
Publication: Journal of Hydraulic Engineering
Volume 122, Issue 12
Abstract
Water surface profiles measured in a laboratory compound channel that has rough floodplains and multiple critical depths are compared with computed water surface profiles obtained by numerical solution of the one-dimensional equation of gradually varied flow in a form that includes a compound channel Froude number. Manning's n is found to vary with depth in the floodplain, and the interaction between the main channel and floodplain is represented as a correction to the main channel resistance coefficient. Outside the discharge range of multiple critical depths, good agreement is demonstrated between measured and computed water surface profiles. Within the discharge range of multiple critical depths, the measured water surface profile near a free overfall cannot be computed as a one-dimensional flow because it separates into distinctly different drawdown profiles in the main channel and floodplain. A method is proposed for identifying the discharge range within which multiple critical depths exist in order to identify potential problems with interpretation of water surface profiles computed by one-dimensional methods in this range.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 122 • Issue 12 • December 1996
Pages: 703 - 709
Copyright
Copyright © 1996 American Society of Civil Engineers.
History
Published online: Dec 1, 1996
Published in print: Dec 1996
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