The Stegbach stream passes under the Aare canal in Obergösgen in what is known as a culvert. This was built during the construction of the Gösgen hydroelectric power station during the years 1914 to 1917 and now has to be repaired. On the almost 100 meter long structure, damage to the concrete and erosion damage have been discovered that in some cases have led to the iron reinforcing rods becoming exposed. As a first step the damaged parts of the culvert will be cleaned using an abrasive high-pressure water jet technique and subsequently rebuilt and sealed using new mortar or concrete.
The refurbishing work started in the middle of March and depending on the water conditions in the Stegbach stream, will take around six months. The costs for the refurbishment amount to some CHF 900,000. The client is Alpiq Hydro Aare AG in Boningen. Both the canal and the Stegbach culvert are owned by them. Alpiq places great value upon a professional and practical maintenance of its plants in order to guarantee a high availability of the power stations. The work is being carried out by the company Betosan AG, based in Wangen b. Olten. Access to the building site takes place exclusively from the south using the roads Kreuzweg and Aareweg.