Rosshaupten reservoir dam is fully open and operational in Germany following a 16-month remediation project. The project was successfully completed in July 2019, with the opening ceremony held in mid September.
As part of the project, developer Uniper Kraftwerke GmbH commissioned Bauer with execution of the 13,500m² diaphragm wall to seal the dam. This project posed a particular challenge: the diaphragm wall could only be built from the very narrow 11m-wide dam crest. To make things more complicated, the crest was located unfavorably on the side of the dam rather than in the middle. The diaphragm wall, which is 1m thick and 7 m deep, includes socketing into very hard rock and was executed in two steps.
First, excavation of the upper 40 m of the dam body was carried out with the help of a diaphragm walling grab on a Bauer MC 64 duty-cycle crane. The remaining 30m, beneath the actual dam body, was excavated using a trench cutter on an MC 96 duty-cycle crane. Bauer carried out the construction work for the diaphragm wall seven days a week in day and night shifts.
Idyllically located near Neuschwanstein castle, in an area known as the “king’s nook” in Bavaria, lake Forggensee is fed by the Lech river and serves as both a local recreational area and a tourist destination. The fifth-largest lake in Bavaria and the largest reservoir in Germany in terms of area, it also generates electricity and provides flood control when the snow melt begins in the Alps.
To prepare the power plant and the flood control for the future, the dam seal was renovated by Bauer Spezialtiefbau GmbH from March 2018 through April 2019.