Gösgen hydropower plant, modernisation of the Winznau weir

The Winznau weir requires refurbishment in order to comply with guidelines and regulations relating to discharge capacity and seismic safety. Between 2023 and 2030, Alpiq Hydro Aare AG will implement the renovation of the structure. All information on the consultation process here: arp.so.ch/aktuell.

The new concession for the operation of the Gösgen hydropower plant entered into force on 1 January 2020. Among other things, it encompasses the modernisation of the Winznau weir. The reconstruction and modifications are based on the latest federal legal provisions and take into account future requirements with regard to flood and seismic safety. In order to meet these requirements, Alpiq is completely modernising the weir, which dates back more than 100 years. The construction work began at the end of 2022 and will take approximately five years.

Who is Alpiq Hydro Aare AG?

Alpiq Hydro Aare AG is a wholly owned subsidiary of Alpiq. The company owns and operates the three run-of-river power plants on the River Aare in the canton of Solothurn.

Discover more

The new concession and the main modernisation measures

1 Modernisation of the Winznau weir

2 Reinforcement of the embankments along the Aare Canal

3 New fish ladder at the Gösgen hydropower plant

Other compensatory and substitution measures

The Aare in the Niederamt region in the canton of Solothurn between Winznau and Niedergösgen (top right).

Logging

In order to free up space for the construction installation sites, an area of around 700 square metres east of the weir was temporarily cleared of trees and bushes in December 2022.

Schedule

The schedule for the renovation of the weir is currently in preparation.

Your questions, our answers

Why – in contrast to earlier plans – the characteristic weir bridge may now be retained? Where can I cross the river during the construction period? Will there be a swimming area with a sandbank below the weir? Find the answers to your questions here.