Numerical and physical model studies for hydraulic flushing of sediment from Chamera-II reservoir, Himachal Pradesh, India

Storage capacity of reservoirs across the world is reducing due to sediment deposition and sediment management is important for sustaining the useful life of reservoirs. Sediment management is the governing criteria for the design and operation of new projects. The recent trend is to plan and operate run-of-the-river hydroelectric power projects based on the above criteria. Hydraulic flushing of sediment deposition is an effective option in many of such projects. Since the design and operation of the projects are unique, physical and numerical models can be used for simulating the flushing process and optimizing the design. Chamera Hydro-Electric Project, Stage-II (Chamera-II) across River Ravi in India was designed as a run-of-the-river scheme with provision for hydraulic flushing of reservoir. One Dimensional mathematical model studies were conducted for predicting the probable sedimentation profile. Experiments were conducted on a 1:70 geometric scale model to simulate flushing operation. Sedimentation profiles and quantity of sediment flushed were measured for alternative flushing discharges and durations. The results were used for finalizing the design and layout of various project components and flushing operation for sustaining the reservoir capacity. The effectiveness of flushing could also be confirmed from the field observations.