Joint Venture Wins Contract

Kraftwerke Oberhasli AG (KWO) has enlisted a joint venture comprising Frutiger AG, Implenia, and Ghelma AG Baubetriebe to replace the existing Spitallamm dam on Lake Grimsel. Implenia holds a 42.5% stake in this joint venture. The overall contract is valued at approximately CHF 100 million.

New Double-Curvature Arch Dam

The Spitallamm dam, originally completed in 1932, is being replaced with a new double-curvature arch dam positioned directly in front of the old dam. This new structure maintains the same crest height but allows for potential height increases to enlarge Lake Grimsel. The dam is 113 meters high and has a substantial concrete volume of 223,000 m³.

Construction Timeline and Expertise

Construction commenced in May 2019, with a planned completion date in October 2025. Implenia is leveraging its infrastructure and underground construction expertise, previously demonstrated in projects like the Vieux Emosson dam in Valais, Switzerland. The project also entails other underground construction work and the preparation of materials for concrete production.

High-Altitude Challenges

The construction poses several challenges, primarily due to its high-altitude location along the Grimsel Pass, ranging from approximately 1,650 meters to 1,980 meters above sea level. Additional complexities arise from balancing the water level hydraulically via a tunnel, while the original dam will remain and be subsequently flooded.

Strategic Infrastructure Upgrade

The Spitallamm dam replacement is crucial for ensuring the future safety and functionality of the dam while accommodating the possibility of enhancing Lake Grimsel's storage capacity. The project underscores the strategic significance of infrastructure upgrades in the region.