Effect of Number of Steps on Energy Dissipation of Stepped Spillways Based on the New Design Approach

Stepped spillways are hydraulic structures that, because of their significant capacity in energy dissipation, have been widely used by designers. Flow mechanism over them is complex and many investigations have been performed to study that mechanism. The effect of some parameters such as the number of steps in energy dissipation has not been fully investigated. In this study the latest design criteria have been reviewed and then an algorithm has been developed to design the stepped spillways which is based on the effect of number of steps. Results show that the number of steps affect the energy dissipation. With increasing the number of steps energy dissipation increases and then decreases. Thus for specific discharge and spillway slope, the number of steps can be optimized for maximum energy dissipation. By reducing design discharge the optimum number of steps increases. Research work on this subject can be continued in the future and various aspects of the design parameters may be investigated.