Inception Point for Embankment Dam Stepped Spillways
Publication: Journal of Hydraulic Engineering
Volume 139, Issue 1
Abstract
Retrofitting embankment dams with stepped spillways has become a common design practice, particularly for those dams that change hazard classification from low to high. For embankment dams retrofitted with stepped spillways, the chute length is often insufficient for developing aerated flow or an inception point. The inception point is a key spillway design parameter used in energy dissipation, flow depth, and air entrainment prediction relationships. Original research for developing an inception-point relationship for stepped spillways was based on primarily gravity () stepped spillways, with the majority having an ogee crest control section. The resulting, inception-point relationship tends to overestimate the inception-point location for broad-crested weir stepped spillways () when the Froude surface roughness () is less than 10. Consequently, research on broad-crested weir stepped spillways retrofitted for embankment dams has been conducted to provide an optimized inception-point relationship. This study provides additional data allowing further refinement (i.e., ) of the inception-point relationship for broad-crested stepped spillways (), and it provides a new relationship for broad-crested weir stepped spillways for .
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References
Boes, R. M., and Hager, W. H. (2003a). “Hydraulic design of stepped spillways.” J. Hydraul. Eng., 129(9), 671–679.
Boes, R. M., and Hager, W. H. (2003b). “Two-phase flow characteristics of stepped spillways.” J. Hydraul. Eng., 129(9), 661–670.
Bung, D. B. (2011). “Developing flow in skimming flow regime on embankment stepped spillways.” J. Hydraul. Res., 49(5), 639–648.
Chamani, M. R., and Rajaratnam, N. (1999). “Characteristics of skimming flow over stepped spillways.” J. Hydraul. Eng., 125(4), 361–368.
Chanson, H. (1994). “Hydraulics of skimming flows over stepped channels and spillways.” J. Hydraul. Res., 32(3), 445–460.
Chanson, H. (2002). The hydraulics of stepped chutes and spillways, A. A. Balkema Steenwijk, The Netherlands.
Chanson, H. (2006). “Hydraulics of skimming flows on stepped chutes: The effects of inflow conditions?” J. Hydraul. Res., 44(1), 51–60.
Chanson, H., and Carosi, G. (2007). “Turbulent time and length scale measurements in high-velocity open channel flows.” Exp. Fluids, 42(3), 385–401.
Chanson, H., and Toombes, L. (2002). “Experimental investigations of air entrainment in transition and skimming flows down a stepped chute.” Can. J. Civ. Eng., 29(1), 145–156.
Chow, V. T. (1959). Open-channel hydraulics, McGraw-Hill, Boston, MA.
Felder, S., and Chanson, H. (2008). “Turbulence and turbulent length and time scales in skimming flows on a stepped spillway. Dynamic similarity, physical modelling and scale effects.”, Hydraulic Model Report CH series, Division of Civil Engineering, The Univ. of Queensland, Brisbane, Australia.
Gonzalez, C. (2005). “An experimental study of free-surface aeration on embankment stepped chutes.” Ph.D. thesis, Univ. of Queensland, Brisbane, Australia.
Gonzalez, C. A., and Chanson, H. (2007). “Hydraulic design of stepped spillways and downstream energy dissipators for embankment dams.” Dam Eng., 17(4), 223–243.
Hunt, S. L., and Kadavy, K. C. (2010a). “Energy dissipation on flat-sloped stepped spillways: Part 1. Upstream of the inception point.” Trans. ASABE, 53(1), 103–109.
Hunt, S. L., and Kadavy, K. C. (2010b). “Energy dissipation on flat-sloped stepped spillways: Part 2. Downstream of the inception point.” Trans. ASABE, 53(1), 111–118.
Hunt, S. L., and Kadavy, K. C. (2010c). “Large-scale stepped spillway testing.” Proc., Association of State Dam Safety Officials Annual Meeting, ASDSO, Lexington, KY.
Hunt, S. L., and Kadavy, K. C. (2011). “Inception point relationship for flat-sloped stepped spillways.” J. Hydraul. Eng., 137(2), 262–266.
Matos, J., Frizell, K. H., André, S., and Frizell, K. W. (2002). “On performance of velocity measurement techniques in air-water flows.” Proc.,. Hydraulic Measurements and Experimental Methods, Wahl, T. L., Pugh, C. A., Oberg, K. A., and Vermeyen, T. B., eds., ASCE, Reston, VA.
Meireles, I., and Matos, J. (2009). “Skimming flow in the nonaerated region of stepped spillways over embankment dams.” J. Hydraul. Eng., 135(8), 685–689.
Pfister, M., and Hager, W. H. (2011). “Self-entrainment of air on stepped spillways.” Int. J. Multiphase Flow, 37(2), 99–107.
Takahashi, M., Gonzalez, C. A., and Chanson, H. (2006). “Self-aeration and turbulence in a stepped channel: Influence of cavity surface roughness.” Int. J. Multiphase Flow, 32(12), 1370–1385.
Wood, I. R., Ackers, P., and Loveless, J. (1983). “General method for critical point on spillways.” J. Hydraul. Eng., 109(2), 308–312.
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© 2013 American Society of Civil Engineers.
History
Received: Oct 7, 2011
Accepted: Jun 11, 2012
Published online: Jul 23, 2012
Published in print: Jan 1, 2013
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