Water march in Abwinden-Asten
11.05.2020Abwinden-Asten, Luftenberg
With all safety and precautionary measures in place, the fish pass at the Danube power plant Abwinden-Asten was put in operation on 11 May 2020, despite the restrictions caused by the coronavirus crisis. The fish pass was completed in winter 2020, but the flooding was postponed to May because of the restrictions. Fish monitoring is scheduled to start on 12 May.
“This was the quickest built fish pass at VERBUND by far,” says a pleased VERBUND project leader David Oberlerchner. The approximately 5 kilometre-long, near-natural river was created in almost a year and constructed in truly record time. “We were always on schedule with all key construction steps,” says Oberlerchner.
The water worked its way only slowly downwards. The initial amount of water at the beginning first had to fill up the gaps in the gravel above the sealing layer. After four hours, the water reached the inlet below the power plant. Project leader Oberlerchner is happy: “It’s done! The first flooding has been a success. The Danube power plant at Abwinden-Asten is now barrier-free. In the coming weeks, we’ll find out which fish are waiting impatiently to swim through.” Because the fish monitoring provided by the technical agency “Blattfisch” from Wels, which specialises in waterbody ecology, gets underway immediately after initial operation.
In late autumn 2019, VERBUND installed two PIT tag stations (PIT = Passive Integrated Transponder, i.e. a microchip similar to the one used to mark dogs and cats) for counting fish. An antenna at the entry and exit of the fish pass and a weir at the entry have been installed. Over the coming years, fish ecologists will scientifically investigate how the fish migrate. The type, size and age of the animals will also be determined. The functionality of the plant will be documented with these data and finally officially confirmed.
Commissioning successful
Due to the crisis-related restrictions, only a few people involved in the construction turned up for the flooding of the Abwinden-Asten fish pass. Complying with the safety distance and wearing a mask, they monitored the inlet structure during the opening of the spillway gate. The river was filled in a controlled way. The spillway gate was initially opened only a few centimetres until the river bed had filled with water and the gate could be opened further.The water worked its way only slowly downwards. The initial amount of water at the beginning first had to fill up the gaps in the gravel above the sealing layer. After four hours, the water reached the inlet below the power plant. Project leader Oberlerchner is happy: “It’s done! The first flooding has been a success. The Danube power plant at Abwinden-Asten is now barrier-free. In the coming weeks, we’ll find out which fish are waiting impatiently to swim through.” Because the fish monitoring provided by the technical agency “Blattfisch” from Wels, which specialises in waterbody ecology, gets underway immediately after initial operation.
Fish ahoy!
After initial operation, it will be monitored whether and which fish are using the fish ladder. The safety of the plant (e.g. of the dams) is ensured by a daily check of the entire facility.In late autumn 2019, VERBUND installed two PIT tag stations (PIT = Passive Integrated Transponder, i.e. a microchip similar to the one used to mark dogs and cats) for counting fish. An antenna at the entry and exit of the fish pass and a weir at the entry have been installed. Over the coming years, fish ecologists will scientifically investigate how the fish migrate. The type, size and age of the animals will also be determined. The functionality of the plant will be documented with these data and finally officially confirmed.
