E6 Clean Water Tunnel
Norway
2022 | ONGOING
The E6 Clean Water Tunnel project involves the construction of a new water supply system for the city of Oslo, with the aim of ensuring greater safety and continuity in the distribution of drinking water and improving the current system, which relies exclusively on Lake Maridalsvannet. Ghella, in joint venture with AF Gruppen, is responsible for the construction of the drinking water distribution system, which includes a tunnel with a diameter of 6 metres and a length of 11 km to be excavated using a double-shield TBM, as well as a system of tunnels of varying diameters totalling an additional 7 km to be excavated using drill-and-blast methods.
In January 2026, after an 11-kilometre journey beneath Oslo, the tunnel boring machine Laila reached its final destination, breaking through into a cavern at Huseby in the presence of approximately 300 guests. The completion of the tunnel excavation, a key element of the new municipal water system, marked a major milestone in the project promoted by the City of Oslo through the Water and Wastewater Authority. Once completed at the end of 2027, the project will enable the Norwegian capital to rely on two water reserves and a redundant water supply system, reducing the risk of service interruptions and improving the overall efficiency of the network.
Benefits
1. Ensures clean water supply for a rapidly growing population
2. Reduces network losses and water wastage