Scouring in Long Contractions
Publication: Journal of Irrigation and Drainage Engineering
Volume 124, Issue 5
Abstract
Based on the continuity of flow and sediment, an analysis on scouring in long contractions is conducted with a formula obtained from measured sediment discharge in long contractions and a formula for the flow resistance related to local scour. The analytical solution shows that the equilibrium scour depth in the contracted section depends only on the ratio of the uncontracted to the contracted channel width, and the approach flow depth. The equation is applicable to both live-bed and clear-water scouring conditions. Previous predictive equations by Straub or Gill can also arrive at the same conclusion, but only for some special cases. A comparison between the measured scour data and various analytical models confirms that the simplified equation is sufficiently accurate for most practical purposes.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Ashida, K. (1963). “Study on the stable channel through constrictions.”Annu. Rep., Disaster Prevention Research Institute, Kyoto University, Kyoto, Japan, 1–15.
2.
Breusers, H. N. C., and Raudkivi, A. J. (1991). “Scouring.”IAHR hydraulic structures design manual 2, A. A. Balkema, Rotterdam, The Netherlands.
3.
Gill, M. A.(1981). “Bed erosion in rectangular long contraction.”J. Hydr. Div., ASCE, 107(3), 273–284.
4.
Harrington, R. A., and McLean, D. G.(1984). “Field observations of river bed scour on the Peace River near Fort Vermilion, Alberta.”Can. J. Civ. Engrg., Ottawa, Canada, 11, 782–797.
5.
Komura, S.(1966). “Equilibrium depth of scour in long constrictions.”J. Hydr. Div., ASCE, 92(5), 17–37.
6.
Laursen, E. M.(1960). “Scour at bridge crossing.”J. Hydr. Div., ASCE, 86(2), 39–54.
7.
Lim, S. Y. (1993). “Clear water scour in long contractions.”Proc., Instn. Civ. Engrs., Maritime & Energy, London, U.K., 101(June), 93–98.
8.
Lim, S. Y.(1997). “Equilibrium clear-water scour around an abutment.”J. Hydr. Engrg., ASCE, 123(3), 237–243.
9.
Rakha, K. A., Helwa, M. F., and El-Khashab, A. M. (1991). “The equilibrium scour depth in river contractions.”Advances in water resources technology, G. Tsakiris, ed., A. A. Balkema, Rotterdam, The Netherlands, 121–127.
10.
Rana, M. Y. (1986). “Flume experiments on sediment bed in steady non-uniform flow,” M/Eng thesis, Asian Institute of Technology, Bangkok, Thailand.
11.
Straub, L. G. (1934). “Effect of channel contraction works upon regimen of movable bed streams.”Trans. Am. Geophysical Union, Part II, 454–463.
12.
Wang, Z., and Kron, W.(1991). “Time distortion in large scale sediment model tests.”J. Hydr. Res., Delft, The Netherlands, 29(2), 161–178.
13.
Webby, M. G. (1994). “General scour at a contraction.”RRU Bull. 73, Bridge Design and Research Seminar, National Roads Board, New Zealand, 109–118.
Information & Authors
Information
Published In
Journal of Irrigation and Drainage Engineering
Volume 124 • Issue 5 • September 1998
Pages: 258 - 261
Copyright
Copyright © 1998 American Society of Civil Engineers.
History
Published online: Sep 1, 1998
Published in print: Sep 1998
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.