Pawana Dam Energy Dissipation – A Case Study

Energy dissipation is one of the important aspects in the life of dams, barrages and outlets. For the medium head projects, hydraulic jump type energy dissipator is a common choice. In case of ogee spillway when flood water is discharged, by the time it reaches the toe of spillway, the potential energy gets converted into kinetic energy. The flow turns into a supercritical flow having lot of erosion potential. The flow can be converted into a subcritical flow by forming a hydraulic jump on the downstream apron. Many dams are suffering and some of them are victims of the inadequate energy dissipation. Location of hydraulic jump plays a vital role to accomplish the task of energy dissipation. Present study is carried out to address this problem and a new technique is proposed to obtain appropriate location of hydraulic jump for variable discharge and corresponding tail water submergence conditions. The technique so developed is applied to the energy dissipator of one of the existing dams and the performance is confirmed by model study. The results and findings are presented herein.