American Society of Civil Engineers


Simple Methods for Energy Dissipation at Culvert Outlets


by Rollin H. Hotchkiss, (Albrook Hydraulics Laboratory, Department of Civil and Environmental Engineering, Washington State University, P.O. Box 642910, Pullman, WA 99164-2910 E-mail: rhh@wsu.edu) and Emily A. Larson, (Hydraulic Engineer, Engineering and Hydrosystems Inc., 8122 South Park Lane, Suite 308, Littleton, CO 80120 E-mail: emily.larson@enghydro.com)
Section: Hydraulics and Structures, pp. 1-12, (doi:  http://dx.doi.org/10.1061/40792(173)443)

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Document type: Conference Proceeding Paper
Part of: Impacts of Global Climate Change
Abstract: Experiments were performed to investigate the energy dissipation realized at the outlet of a culvert using two simple design alternatives: (1) Design I, a simple weir near the culvert outlet, and (2) Design II, a weir with a drop upstream in the culvert outlet barrel. The two designs are intended to reduce the flow energy at the outlet by inducing a hydraulic jump within the culvert barrel, without the aid of tailwater. This paper examines the jump geometry, the effectiveness of each jump type, and proposes a design procedure for practicing engineers. The design procedure is applicable to culverts with approach Froude numbers from 2.6–6.0. Both designs are effective in reducing outlet velocity 0.7 to 8.5 ft/s (0.21–2.59 m/s), momentum 10–48%, and energy 6–71%. The design layouts allow easy access for maintenance activities.


ASCE Subject Headings:
Energy efficiency
Culverts
Energy dissipation
Velocity
Hydraulic jump