Author(s): Gabriele Harb; Clemens Dorfmann; Hannes Badura; Verbund Hydro; Josef Schneider
Linked Author(s): Josef Schneider, Clemens Dorfmann, Gabriele Harb
Keywords: Three-dimensional numerical modelling; Reservoir flushing; Reservoir sedimentation; Flood risk; Field measurements
Abstract: In this study a numerical analysis is carried out to investigate the flushing efficiency in an Alpine reservoir. The reservoir is approximately 4. 5 km long with an initial storage volume of about 1. 4 Mio. m3. Measurements show that 85, 000 m3 of sediments deposit in the reservoir annually. A small amount of the deposited sediments has been eroded and transported through the reservoir in former flushing events. However, echo-soundings performed in 2009 showed that approximately 860, 000 m3 of sediments are already deposited in the reservoir. This represents an annual sedimentation rate of about 6. 1 % of the initial reservoir volume. Echo-soundings performed before and after the flushing event were used to evaluate the morphological changes. The water levels of the critical flood event (20-year flood) before and after the flushing event were modelled using a three dimensional numerical model to evaluate the changes in the water level at different sections. Additional ADCP measurements performed at the prototype were used to validate the computed velocity fields of the numerical model.
Year: 2013