Sediment Evacuation from Reservoirs through Intakes by Jet-Induced Flow

Reservoir sedimentation is considered as a sustainability problem. A concept getting down to the root of the cause was developed and tested in laboratory experiments. The idea is to maintain sediment in suspension, i.e., avoiding its settling near the dam by generating a jet induced artificial flow field and related turbulence (rotational flow), enabling the release of suspended sediment through the power intake. Therefore, a perpendicular jet configuration consisting of four jets arranged in a horizontal plane was investigated in a rectangular basin equipped with an outlet structure. The influence of its geometric parameters and the jet discharge on the sediment release was analyzed in detail. The flow pattern and its effect on the sediment release efficiency were evaluated, by measurements of turbidity and flow velocity. Depending on experiment duration and discharge, an ideal parameter set was identified resulting in a release efficiency between 1.5 and 2 compared to the reference case without jets. (C) 2014 American Society of Civil Engineers.