Australia 
Brazil 
Canada 
Chile 
China 
Columbia 
Denmark 
Egypt 
France 
India 
Indonesia 
Ireland 
Italy 
Malaysia 
New Zealand 
Norway 
Panama 
Peru 
Poland 
Portugal 
Saudi Arabia 
Singapore 
South Korea 
Spain 
Sweden 
Taiwan 
Thailand 
Türkiye 
United Kingdom 
United States 
Vietnam 
The E6 project, also known as the Rentvannstunnel, reached a major milestone on 20 January with the final breakthrough by the ‘Laila’ TBM. This factory train dug 11km under the bedrock of Oslo to build a key infrastructure for the capital’s authorities, who aim to make water transport and supply more reliable and robust.
It will draw water from Holsfjorden, west of Oslo, to a new underground water treatment facility at Huseby, and distribute it across the Norwegian capital.
SYSTRA Italy, in partnership with Sweco Norge, is accompanying underground civil engineering studies on behalf of the AF Gruppen-Ghella consortium, including segments, technical and safety niches, and tunnel boring machine launch structures. This tunnel will be connected to the nerve centre of Oslo’s new drinking water system.
We are proud of the innovative and sustainable solution adopted for the TBM segmental lining design of Oslo’s E6 Clean Water Tunnel. This 11-km tunnel will provide a resilient and reliable water supply for the capital, marking a key milestone in Norway’s infrastructure security.
Paolo Fantini, Senior Geotechnical Engineer, SYSTRA Italy
In addition to the TBM drive, the project includes about 7 kilometres of Drill & Blast tunnels that connect to the existing facilities, including the network associated with the Maridalsvannet water treatment plant, which currently supplies roughly 90% of Oslo’s potable water.
Creating a more robust water supply
Once complete, Oslo’s upgraded clean-water system will strengthen east–west distribution, access larger reservoirs, and provide full backup capacity for the city, improving resilience in case of issues with the existing supply.
Water, a key adjacent market for SYSTRA’s development
In our drive to develop adjacent markets, SYSTRA is accelerating its presence in projects related to water and hydraulic infrastructure, drawing on its expertise in complex underground projects and transport infrastructure.
In addition to a recent contract for a water production plant in Australia and a water tunnel study in India in 2023, the E6 Rentvannstunnel project illustrates how tunnel construction, systems integration and risk management translate into vital infrastructure beyond transport.
