Author(s): Barbara Brinkmeier; Heidi Boettcher; Markus Aufleger
Linked Author(s): Markus Aufleger
Keywords: Fish protection; Downstream migration; Hydro power; Ecological continuity. 1
Abstract: The Flexible Fish Fence is a new fish protection system, developed at the Unit of Hydraulic Engineering of the University of Innsbruck Austria. The concept consists of horizontally arranged steel wires, which pose a mechanical barrier upstream of hydropower plants. Thus, fish are physically and behaviorally detained from passing the turbines. During normal operation, the wires are in place, whereas during high flows they are released and hence lying on the river bed. The entire cross section is then available for discharge of water, bed load and floating matter. The steel wires are cleaned during the releasing process. In case of local clogging during normal operation, individual wires or wire clusters can be released in order to clean the inflow area. The concept can be implemented at overflowed power plants or existing power plants, where the ecological continuity has to be recovered. Floating matter entering the inlet structure during a flood or during the cleaning process can be discharged over the plant or rather be extracted by existing trash rack cleaning system. First experiments were performed in the hydraulic laboratory of the University of Innsbruck to demonstrate operating conditions and the functionality of the Flexible Fish Fence. The Flexible Fish Fence can be located in front of the power house, connecting the river bank and the middle pier in an inclined exposition. Due to the horizontal inclined inflow condition, fish are guided along the screen to a fish pass located in the middle pier. In addition the horizontal position of the wires offers a better fish protection than vertical arranged bars. Oscillations of the wires induced by the flow might have an additional deterrent effect and thus enhance the protective purpose. Additional ecological and technical investigations are on the way.
Year: 2013