EXPERIMENTAL INVESTIGATION OF AN OGEE STEPPED SPILLWAY WITH PLAIN AND SLOTTED ROLLER BUCKET FOR ENERGY DISSIPATION

Terminal structure of an ogee spillway plays a major role in dissipating specific energy of surplus water. Release of water from crest to toe of spillway creates high intensity of kinetic energy. This will cause scour and erosion on downstream face of spillway. In the past various types of energy dissipaters have been recommended for ogee spillway but they have limitations of energy dissipation, scouring and erosion problems. Therefore the need arises to provide a suitable energy dissipater to reduce intensity of kinetic energy and safely discharge surplus water at its downstream end. In this research, an attempt has been made to develop a physical model of an ogee profile stepped spillway for Khadakwasla dam with plain and slotted roller bucket as an energy dissipater. Laboratory experiments were performed for a design discharge with varying heads considering four combinations of ogee profile stepped spillway with plain and slotted roller bucket. It is found that the combination of stepped spillway with slotted roller bucket model (SSRB) at 6 m head dissipates specific energy (83.36 %), which is highest among all the combinations.