Media release

Implenia wins contract as part of consortium to replace dam at Grimselsee

Consortium to build new Spitallamm arch dam | Contract worth total of around CHF 100 million

Dietlikon, 25 March 2019 – Kraftwerke Oberhasli AG (KWO) have asked a consortium (“ARGE Grimsel”) consisting of Frutiger AG (lead manager), Implenia and Ghelma AG Baubetriebe to replace the Spitallamm dam on the Grimselsee reservoir. Implenia has a 42.5% stake in the consortium, and the total contract is worth around CHF 100 million.

The existing Spitallamm dam was built almost 90 years ago in 1932, and now needs replacing. The new double-curvature arch dam is to be built directly in front of the old dam wall. The crown of the new structure is as high as the old arch-gravity dam, though if the Grimselsee reservoir is enlarged at a later stage, it will be possible to increase the height. The wall (without reservoir enlargement) will be 113 metres high. The old dam will remain in place and will be filled on both sides. A tunnel will be built to help maintain the hydraulic balance of the water level. Alongside some further underground structures, the contract also includes the processing of materials to produce more than 220,000 m3 of concrete. Work begins in summer 2019 and should last until 2025.

Implenia brings its proven expertise in infrastructure and underground construction to the consortium. It already successfully demonstrated the required skills when it increased the height of the Vieux Emosson dam in Canton Valais.

The new double-curvature arch dam is to be built directly in front of the old dam wall. The old dam will remain in place and will be filled in on both sides. (Image: KWO / David Ormerod)

Contact for media:

Reto Aregger

Head of Corporate Communications

Tel.: +41 58 474 74 77



Implenia is Switzerland’s leading construction and construction services company. It also has strong positions in the German, French, Austrian, Swedish and Norwegian infrastructure markets, as well as significant building construction and civil engineering operations in Germany and Austria. Established in 2006, Implenia can look back on around 150 years of construction tradition. It brings the expertise of its highly skilled construction units together under the roof of a company active throughout Europe. With the broad offering of Implenia and the deep experience of its specialists, the Group can manage a building project through its entire lifecycle and deliver work that is economical, integrated and customer-centric. The focus is on striking a sustainable balance between financial success and social and environmental responsibility. Implenia, with its headquarters in Dietlikon near Zurich, employs more than 10,000 people in Europe and posted revenue of around CHF 4.4 billion in 2018. The company is listed on the SIX Swiss Exchange (IMPN, CH0023868554). More information can be found at www.implenia.com.