Lower Tuxbach water transfer
Underground Mining Power station construction
The STRABAG - JÄGER consortium was charged with the construction of an 8.6-km water transfer channel and the construction of a power plant in the Tyrolean Zillertal.
In the spring of 2017, Verbund AG started with the construction of a new water transfer between the Tuxertal Valley and the Stillup reservoir, to be completed by the end of 2019.
As a successor solution to the Bösdornau power plant, whose operating licence expires in 2019, the water from the Tuxbach will in the future generate electricity via the existing Stillup reservoir. The gradient difference also allows the construction of a small power plant with two Francis turbines that will process 6 m³/s with an installed capacity of 1.7 MW.
The tunnels of the “Lower Tuxbach” project are being excavated partly with a tunnel boring machine and partly using conventional tunnelling.
The ground-breaking ceremony took place on 17.02.2017; the structures will be completed by the end of 2019.
The breakthrough at the Tuxertal Valley took place on 14.07.18 after 246 working days and a tunnelling length of 4,444 m. An 80-metre reverse drive had been previously been required for geological reasons.
A festive breakthrough celebration took place in the presence of the Mayor of Mayrhofen, tunnel sponsor Monika Wechselberger, on 16.07.18.
At the same time as the tunnelling operation was taking place, the water intake and intake tunnel were built in the Tuxertal Valley, so that, once all parts of the system were complete, all it would take to fill the intake waterway would be to open the bulkheads. The tunnelling operations were dogged for much of their length by major instances of water ingress, which were resolved by the subsequent installation of a ring concrete inner lining.
The tunnel boring machine and the entire trailing gear installation have been dismantled and returned to the starting point at Zemmbach, where excavation of the second, roughly 3.8 km-long section to the final destination at the Stillup reservoir has been underway since the autumn of 2018.