Bottom Slot Discharge Outlet for Combined Sewer Diversion Structure
Publication: Journal of Hydraulic Engineering
Volume 137, Issue 2
Abstract
The concept of a bottom slot outlet was developed to serve as a combined sewer overflow diversion structure to convey flow to deep tunnel storage under free discharge conditions and pass the remaining volume once storage capacity is exceeded with minimum backwater effects. In order to test the concept, a 1:19.5 scale model was constructed and tested over a range of discharges in order to determine the required slot length to pass a certain discharge. Different bottom slopes and slot widths were tested. For subcritical approach flow, the flow in the structure passed through critical depth at the upstream end of the slot, eliminating the possibility of backwater effects. The results were found to be nearly independent of the bottom slope for typical small slopes in sewer systems, and a simple dimensionless relation was developed to relate the slot length to other parameters. A mathematical model combining continuity and energy relations for the remaining flow in the structure with an orifice relation for flow through the slot was capable of reproducing the observed experimental results.
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References
Anderson, J. J. (1970). “Real-time computer control of urban runoff.” J. Hydr. Div., 96(1), 153–164.
Bouvard, M. (1953). “Discharge passing through a bottom grid.” Houille Blanche, 8, 290–291 (in French).
Cahoon, J., and Hoshino, T. (2003). “Flume for teaching spatially varied open channel flow.” J. Hydraul. Eng., 129(10), 813–816.
Drobir, H., Kienberger, V., and Krouzecky, N. (1999). “The wetted rack length of the Tyrolean weir.” IAHR 28th Congress, IAHR, Madrid, Spain.
Fischer, H. B., List, E. J., Koh, R. C. Y., Imberger, J., and Brooks, N. H. (1979). Mixing in inland and coastal waters, Academic, San Diego.
Garcia-Salas, J. -C., and Chocat, B. (2005). “1-D modeling of side-weir CSOs.” Houille Blanche, 42(2), 63–71.
Hager, W. H. (1999). Wastewater hydraulics: Theory and practice, Springer-Verlag, Berlin.
Henderson, F. M. (1967). Open channel flow, Macmillan, New York.
Hudson, D. M. (1998). “Inflatable gates improve storage, reduce CSO.” Public Works, 129(2), 54, 56, 58.
Kuntzmann, J., and Bouvard, M. (1954). “Theoretical study of bottom type water intake grids.” Houille Blanche, 9, 569–574 (in French).
Mostkow, M. A. (1957). “Theoretical study of bottom type water intake.” Houille Blanche, 4, 570–580 (in French).
Nasser, M. S., Venkataraman, P., and Ramamurthy, A. S. (1980). “Curvature corrections in open channel flow.” Can. J. Civ. Eng., 7(3), 421–431.
Oliveto, G., Biggiero, V., and Hager, W. H. (1997). “Bottom outlet for sewers.” J. Irrig. Drain. Eng., 123(4), 246–252.
Olson, R. M., and Wright, S. J. (1990). Essentials of engineering fluid mechanics, 5th Ed., Harper and Row, New York.
Ramamurthy, A. S., Qu, J., and Vo, D. (2007). “Simulation of flow past an open channel floor slot.” J. Hydraul. Eng., 133(1), 106–110.
Ramamurthy, A. S., and Satish, M. G. (1986). “Discharge characteristics of flow past a floor slot.” J. Irrig. Drain. Eng., 112(1), 20–27.
Schutze, M., Campisano, A., Colas, H., Schilling, W., and Vanrolleghem, P. (2004). “Real time control of urban wastewater systems—Where do we stand today?” J. Hydrol., 299(3–4), 335–348.
Uyumaz, A., and Smith, R. H. (1991). “Design procedure for flow over side weirs.” J. Irrig. Drain. Eng., 117(1), 79–90.
Wu, I. P., and Gitlin, H. M. (1975). “Energy gradient line for drip irrigation laterals.” J. Irrig. Drain. Div., 101(4), 323–326.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 137 • Issue 2 • February 2011
Pages: 248 - 253
Copyright
© 2011 ASCE.
History
Received: Jul 25, 2008
Published online: Mar 16, 2010
Accepted: May 26, 2010
Published in print: Feb 2011
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