Investigation of energy dissipation and flow regime over various forms of stepped spillways

The efficient operation of reservoirs relies on efficient release of water during flooding, requiring a good understanding of spillway hydraulics. Some experiments were conducted in a laboratory flume on a stepped spillway model with moderate slope (26.6º) for discharges up to 0.0121 m3/s. Using regular uniform horizontal steps of 5 cm height, several new step configurations including inclined and horizontal curved steps with and without reflector blocks were used. The energy losses over a horizontal stepped spillway were compared with those obtained in a number of previous studies, and with the results obtained for the new step configurations. Good agreement was shown with previous results for horizontal steps, and the inclined and horizontal curved steps dissipated about twice as much energy as the horizontal steps. The results highlight the importance of considering a variety of step forms in spillways where flows are unpredictable and energy dissipation is important.