The E06 “Clean Water” tunnel is at the centre of the project to modernise Oslo’s water supply. The aim is to ensure a 100 per cent water supply by replacing the existing infrastructure with 18 kilometres of underground tunnels. The Municipality of Oslo has entrusted AF Ghella with the realisation of this project. The aim is to create a new water distribution network between Huseby, Oset and Stubberud in order to build up a water reserve. The project includes the construction of a drinking water supply system with
transmission pipelines, pumping stations, clean water storage tanks and connections to existing pipelines and the Oset water treatment plant. The new system also connects the Holsfjorden water supply tunnel, the underground water treatment station at Huseby and the tunnel for transferring pre-treated water from Huseby to Stubberud. It strengthens the connectivity between East and West Oslo to ensure a reliable drinking water supply.

Currently, Lake Maridalsvannet supplies 90% of Oslo’s drinking water, so this new distribution system, which includes 18 kilometres of tunnels, is crucial. Of these, eleven kilometres will be bored using a tunnel boring machine (TBM) and seven kilometres by conventional means.

SOTRALENTZ CONSTRUCTION is contributing to the project by supplying around 3,000 tonnes of steel, which corresponds to around 6,000 rings in three different types.