Experimental and numerical simulations of the hydraulic flushing of reservoir sedimentation for planning and design of a hydropower project

Abstract Hydropower projects located on rivers transporting heavy sediment loads require design and operation criteria based on sediment management as a means of sustaining the project life. Sediment management is achieved by designing projects as a run‐of‐the‐river scheme, with provision for drawdown flushing, noting hydraulic model simulations are essential for optimizing the design of these projects. Sediment deposition levels are generally predicted with long‐term simulations using 1‐D numerical models, as well as experiments with scaled physical models that simulate drawdown flushing. The present study presents experiments with scaled model and 3‐D numerical model simulations conducted for hydraulic flushing of a reservoir. Experiments were conducted for various durations and discharges to finalize the intake alignment and optimize the flushing. The results of the 3‐D numerical model simulations are in agreement with the results of the experimental study (4%–6% variation). The results also indicate a combination of a 1‐D numerical model for sedimentation and a 3‐D numerical model for flushing can be effectively used to simulate the sedimentation and flushing of reservoirs during the planning and design stages.