Cloudburst tunnel in Valby

Another significant milestone for Eiffage Infra Specialised Civil Engineering: Together with the main contractor MT Højgaard Danmark, our company has been commissioned to implement one of the largest infrastructure projects in the Copenhagen area - the construction of the approximately 2.4 km long cloudburst tunnel in Valby.

The aim of the project is to better protect the neighbourhoods of Valby and Frederiksberg West against heavy rainfall events and so-called "cloudbursts". The tunnel serves as an underground retention basin that can hold up to 30,000 cubic metres of rainwater. This is roughly nine times the volume of the water-filled Round Tower, one of Copenhagen's landmarks. The water is then channelled to the sewage treatment plant in a controlled manner. Only in extremely exceptional cases is it released via outlets into natural watercourses such as the Gåsebækrenden or the Enghave Canal - a targeted contribution to the protection of the nearby Kalveboderne Natura 2000 area. The tunnel starts in the F.L. Smidth area in Valby and runs deep through the limestone under well-known neighbourhoods such as Grønttorvet, Valby Idrætspark, Valbyparken and Musikbyen in Sydhavnen. Construction work started in the summer of 2024 and the tunnel and pumping station are scheduled for completion in 2028.

With a contract volume of around DKK 490 million, the project is one of the largest in the Danish climate protection programme. The tunnel is part of a comprehensive plan of hundreds of cloudburst projects to make Frederiksberg and Copenhagen more resilient to extreme weather. Eiffage Infra Spezialtiefbau was chosen as a reliable partner thanks to our extensive experience in specialised civil engineering and tunnelling, including similarly complex projects. "Such a large project places high demands - we have the expertise to successfully realise it together with MT Højgaard," says Carsten Lund, CEO of MT Højgaard Danmark.

The current status of the work is promising: the first shaft with the abbreviation "ENG" has been completely drilled and excavation is imminent. At the same time, our drilling rigs have been strategically distributed: Drill rig 1 has already started its move to shaft "MUS", while drill rig 2 is now moving into position at shaft "BLU". This means that the team is working on all four shafts simultaneously - an important milestone in the course of the project. Meanwhile, shaft "FLS" is being supervised by our joint venture partner so that the entire shaft programme is fully utilised. This bundled approach not only speeds up the project, but also emphasises the excellent cooperation within the entire team and with our partners. The importance of the project is also emphasised by the clients HOFOR and Frederiksberg Forsyning: it not only protects people and property, but also creates greater safety for the affected urban areas - an investment in the future of urban infrastructure.

The contract includes:
- The construction of four working shafts
- The excavation of three main tunnel sections
- The installation of the tunnel tubes
- The connection to existing sewers via two structures
- The construction of an emptying pumping station on the Enghave Canal