Hydraulic Design of Stepped Cascades, Channels, Weirs and Spillways
Stepped channels and spillways have been used for more than 2500 years, but recently new construction materials have renewed interest in stepped chutes. The steps significantly increase the rate of energy dissipation taking place on the spillway face and reduce the size of the required downstream energy dissipation basin. Stepped cascades are also used in water treatment plants to enhance the air-water transfer of atmospheric gases and of volatile organic components. This book presents new material on the hydraulic characteristics of stepped chute flows. Two different flow regimes can occur: nappe flow regime for small discharges and flat channel slopes; and skimming flow regime - the hydraulics of each flow regime are described. The book also covers the effects of flow aeration and air-bubble entrainment as well as the process of air-water gas transfer taking place above the stepped chute. Practical examples of hydraulic design and a critical review of the risks of accidents and failures with stepped channels makes this book a useful reference tool for professional engineers, postgraduates and researchers in the field.
- Hardback | 261 pages
- 165.1 x 241.3 x 25.4mm | 612.35g
- 01 Jan 1995
- ELSEVIER SCIENCE & TECHNOLOGY
- Amsterdam, Netherlands
- references, appendices, index
Table of contents
Part 1 History of stepped channels and weirs: history of stepped chutes; ancient irrigation canal systems; discussion. Part 2 Nappe flow regime: hydraulic characteristics of Nappe flows; energy dissipation; air entrainment in Nappe flow regime; design of chutes with Nappe flow regime; example of application. Part 3 Skimming flow regime (1) - hydraulics of skimming flows: onset of skimming flow; boundary layer growth; uniform flow conditions; flow resistance; velocity distribution; examples of application. Part 4 Skimming flow regime (2) - energy dissipation: presentation; head loss calculations; residual energy; discussion; examples of application. Part 5 Air-water gas transfer on stepped chutes: prediction of air-water gas transfer; Nappe flow regime; skimming flow regime; discussion - comparison between Nappe and skimming flows; examples of application. Part 6 Design of stepped channels and chutes: design of stepped fountains; concrete stepped spillways and weirs; Gabion stepped weirs and chutes; earth dam spillway with precast concrete blocks; timber dams and crib dams; debris dams. Part 7 Accidents, failures and safety of the design: presentation; failures and accidents; safety features for stepped channels.