The design of a channel involves the selection of channel alignment, shape, size, and bottom slope and whether the channel should be lined to reduce seepage and/or to prevent the erosion of channel sides and bottom. Since a lined channel offers less resistance to flow than an unlined channel, the channel size required to convey a specified flow rate at a selected slope is smaller for a lined channel than that if no lining were provided. Therefore, in some cases, a lined channel may be more economical than an unlined channel.
Procedures are not presently available for selecting optimum channel parameters directly. Each site has unique features that require special considerations. Typically, the design of a channel is done by trial and error. Channel parameters are selected and an analysis is done to verify that the operational requirements are met with these parameters. A number of alternatives are considered, and their costs are compared. Then, the most economical alternative that gives satisfactory performance is selected. In this process, it is necessary to include the maintenance costs while comparing different alternatives. Similarly, the costs of energy required if pumping is involved and, for power canals, the amount of revenues produced by hydropower generation must be included in the overall economic analysis.
The channel design may be divided into two categories, depending upon whether the channel boundary is erodible or non-erodible. For erodible channels, flow velocities are kept low so that the channel bottom and sides are not eroded. The minimum flow velocity in flows carrying a large amount of sediment should be such that the material being transported is not deposited in the channel.
In this chapter, we first consider the design of rigid-boundary channels and then the design of erodible channels.
KeywordsTractive Force Channel Side Bottom Slope Side Slope Channel Design
Unable to display preview. Download preview PDF.
- Amer. Soc. Civil Engrs., 1979, Design and Construction of Sanitary and Storm Sewers.Google Scholar
- Blench, T., 1957, Regime Behaviour of Canals and Rivers, Butterworth, London.Google Scholar
- Brandon, T. W. (ed.), 1987, River Engineering Part 1, Design Principles, vol.7, Institution of Water and Environmental Management, London.Google Scholar
- Central Board of Irrigation and Power, 1968, Current Practices in Canal Design in India, New Delhi, India, June.Google Scholar
- Chow, V. T., 1959, Open Channel Hydraulics, McGraw-Hill Book Co., New York, NY.Google Scholar
- Fortier, S. and Scobey, F. C., 1926, “Permissible Canal Velocities,” Trans. Amer. Soc. Civil Engrs., vol. 89, pp. 940-956.Google Scholar
- Gupta, R. S., 1989, Hydrology and Hydraulic Systems, Prentice Hall, Englewood Cliffs, NJ.Google Scholar
- Lane, E. W., 1955, “Stable Channel Design,” Trans. Amer. Soc. of Civil Engrs.Google Scholar
- Lacey, G., 1930, “Stable Channels in Alluvium,” Paper 4736, Proc., Institute of Civil Engrs., vol. 229, London.Google Scholar
- Ranga Raju, K.G., 1983, Flow Through Open Channels, Tata McGraw Hill, New Delhi, India.Google Scholar
- U. S. Army Corps of Engineers, 1970, Hydraulic Design of Flood Control Chan-nels, Report EM 1110-2-1601.Google Scholar