Author(s): Hannes Badura; Josef Schneider; Helmut Knoblauch
Linked Author(s): Helmut Knoblauch, Josef Schneider
Keywords: Reservoir; Flushing; Silting; Sediment transport; Hydraulic structures; Erosion
Abstract: At the Bodendorf run-off-river hydro power plant great efforts have been taken to perform regular reservoir flushes. As part of the EU Interreg IIIB Project ALPRESERV “Sustainable Sediment Management in Alpine Reservoirs” (www. alpreserv. org), several groins have been installed at the beginning of the reservoir. Furthermore, a flushing channel has been excavated in order to improve erosive processes. Extensive monitoring during the flushing event in 2004 has accounted for both erosion and its impact on sediment transport. By means of reservoir measurements and the design of digital terrain models before and after the flushing, a mass budget concerning erosion and sediment deposition has been implemented. From sediment measurements and calculations, conclusions have been drawn regarding the natural sediment transport upstream. By gauging the suspended sediment load at three different locations, the rate of suspended sediments in the entire transport system could be specified. Grain size analyses in the reservoir have conveyed the grain distribution after the flushing. This monitoring project aims at recording the exact sequence of events during the flushing. Looking ahead to the future, it may form the basis for improvements in the flushing procedure, particularly concerning discharge times and minimal water supply. Finally, it has become the basis for optimizing flushing intervals with regard to their economical and ecological compatibility downstream.
Year: 2005