Modification of stepped spillway for hydraulic investigation

Abstract

The terminal structure of a spillway plays a major role in dissipating specific energy of excess flood to safeguard the river channel and downstream structure. The ogee profile spillway is hydraulically efficient, structurally stable and more adequate to dispose excess flood effectively on downstream end of river channel. This spillway will be helpful to control the erosion, scouring and pondage if suitable energy dissipater provided at terminal structure. Due to high discharge of excess flood there are chances of causing erosion on Spillway bed, which is a major problem to affect the spillway capacity. Excess air entrainment causes positive pressure on spillway bed and helpful to achieve maximum energy dissipation by replacing ogee profile by steps. But there are chances of erosion on the nosing of steps which ultimately leads to the failure of structure so to reduce the erosion on nosing and maintain the minimum energy dissipation the sharp edges are converted into curves at specified radius. Therefore, after testing we can conclude that this spillway is best suitable for energy dissipating to overcome the spillway problems by enhancing minimum energy dissipation or not.