Modeling of Sediment Management for the Lavey Run-of-River HPP in Switzerland

Abstract

Reservoir sedimentation hinders the operation of the Lavey run-of-river hydropower plant (HPP) on the Rhone River in Switzerland. Deposits upstream of the gated weir and the lateral water intake reduce the flood release capacity and entrain sediments into the power tunnel. Past flushing operations of the relatively wide and curved reservoir have been inefficient. To improve sediment management, the enhanced scheme Lavey+ with an additional water intake and a training wall for improving flushing was set up. The performance of the enhancement project was tested on a physical model. For its calibration, sediment transport, deposition, and flushing of the present scheme were investigated and compared with prototype measurements. The enhanced scheme was then analyzed in detail to define the flushing discharge and duration, and define the gate operation to ensure maximal erosion of deposits with minimal water loss.