INVESTIGATION AND EVALUATION OF THE PRESSURE FLUSHING THROUGH STORAGE RESERVOIR

Abstract

When a dam is constructed on the rivers, it causes the sediments settle in the reservoir. Therefore, the initial storage of the reservoir would reduce and it will have negative effects on the operation of the reservoir. Considering the importance of this issue, different methods for control of sedimentation and maintenance of dams are used. These methods include: watershed management, dredging, density current venting and flushing. In flushing methods, the previously deposited sediment would be flushed from the reservoir by opening of the outlets. In the pressure flushing the amount of the flushed sediments depend on many parameters such as water depth on the bottom outlets, discharge released through bottom outlets, the size of the outlets, the geometry of the reservoir, the size and the kind of the deposited of the sediments in the reservoir. In this study, the effects of discharge released from the bottom outlets and the water depth on the bottom outlets was investigated using three sizes of non-cohesive sediments (fine, medium and coarse). Laboratory experiments were carried out to investigate the flushing processes during pressure flushing. A physical model was constructed in the