Determining Air Demand for Small- to Medium-Sized Embankment Dam Low-Level Outlet Works
Publication: Journal of Irrigation and Drainage Engineering
Volume 137, Issue 12
Abstract
Air vents in low-level outlet works are installed downstream of control gates or valves to mitigate subatmospheric pressures locally and reduce the potential for damaging cavitation. Published air-vent-sizing methods, which have been limited to large-dam outlet geometries (in-line vertical slide gate), are not applicable for small- to medium-sized embankment dam low-level outlet geometries in which the slide gate is installed on the upstream sloping face of the dam. The water-discharge and air-demand characteristics of a lab-scale low-level outlet works, with the inlet installed on a sloping floor (representing the upstream face of an embankment dam), were evaluated experimentally with respect to gate design (round or rectangular), gate opening, driving head, and outlet submergence; the results are reported herein. Discharge coefficients for predicting low-level outlet works discharge rates (vented or nonvented), and a methodology for air-vent sizing for small- to medium-sized embankment dams are also presented.
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Acknowledgments
Funding for this study was provided, in part, by the State of Utah through the Utah State Office of Dam Safety, United States Geological Survey (USGS), and the Utah State University through the Utah Water Research Laboratory (UWRL).
References
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Information & Authors
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Published In
Journal of Irrigation and Drainage Engineering
Volume 137 • Issue 12 • December 2011
Pages: 793 - 800
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Jun 3, 2010
Accepted: Jan 21, 2011
Published online: Jan 24, 2011
Published in print: Dec 1, 2011
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