Author(s): Manuel Ploerer; Stefan Achleitner; Johann Neuner; Markus Aufleger
Linked Author(s): Markus Aufleger
Keywords: Lpine Reservoir; Sedimentation; Flushing; Hydraulic model test; 2D numerical simulation
Abstract: In the Alps, annual reservoir sedimentation amounts to approximately 0. 2 % of the capacity. Although this value is low compared to the worldwide annual capacity reduction, it is necessary to guarantee an effective sediment management. Reservoir flushing as a measure to avoid and/or to counteract sedimentation is tested within a combination of a hydraulic model test with moveable bed and a complementary 2D numerical simulation. A projected water intake with arch dam is investigated as a laboratory model with a scale of 1: 30. Mean yearly sedimentation scenarios with half annual and annual bed load volumes are used as initial sedimentation scenarios in the experiments. The flushing is modelled in different ways, using steady discharges and unsteady flood hydrographs. Next to the testing of these regular flushings of accumulated sediment bodies, two historic extreme events (Aug 1987, Sept 1999) are modelled. Therein, the sediments are introduced with the flood discharge to the reservoir. The used grain-size distribution is chosen according to the mobilized bed load material. The introduced volumes during the events are up to three times of the annual bed load quantity. The results of the described scenarios provide important calibration parameters for 2D numerical simulations of the sedimentation and flushing processes. The final goal is to reliably apply a numerical model to a second intake structure without the need of a demanding laboratory model.
Year: 2013