Author(s): C. Dorfmann; H. Knoblauch
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Keywords: No Keywords
Abstract: The river run-of hydro power plant Feistritz at the river Drau, Austria, was built between 1965 and 1968 to generate electricity. The owner is the Verbund Austrian Hydro Power Company (AHP). The impoundment formed a 15 km long reservoir with maximal water depths of 20 m. After 40 years of operation the hydro power plant has encountered severe sedimentation problems. 90% of the annual sediment inputs of 1,000,000 m3 are deposited within the reservoir. A yearly performed monitoring indicates the increasing amount of deposited sediment. At the time each year 150,000 m3 are dredged to remove sediment from the inlets to the turbines and to keep a channel open for discharges in the case of floods. In a first step of encountering the problem of unregulated sedimentation, training structures will be built to ensure the transport of suspended sediment in cases of flushing. The idea is to decrease the water level by 2.5 m, so that in the case of a flood a so-called “soft flushing” is performed. In this case the suspended sediment should be transported into the tailwater of the hydro power plant. Both a physical model (scale 1:100) and a 2d numerical model are to show the optimal line management and the location of the training structures. First results of the numerical 2d model show the velocity distribution in the case of floods. A recently performed ADCP measurement (1200 k Hz RDI) indicates the flow conditions in the reservoir and provides an excellent basis for the numerical calculation.
Year: 2009