Byggeindustrien reports that AF Ghella Tunnel Boring Machine has bored 440 meters of Rentvann water tunnel since December. In addition, 4,8 kilometers of the total 7 kilometers long access tunnels have been excavated.

It is a project of the water and wastewater agency in Oslo. The aim of the project is to provide a second water supply to Oslo, Europe's fastest growing city. Currently Oslo's main water supply is Maridalsvannet. The Oslo Commune aims to decrease the risk of being dependent on one water source.

This project has several sub project. One involves, for example, construction of a 19 kilometer long raw water tunnel from Holsfjord at Vefsrud in Lier municipality through Lier, Hole and Bærum municipality, to Huseby west in Oslo.

Parts of the tunnel that leads Råvann from Holsfjorden to Oslo will go below the ground from the municipal boundary in Bærum under Røa to Huseby. Under Husebyskogen, a state -of -the -art water treatment plant will be built that will be able to supply the entire Oslo population with clean drinking water.

In connection with the underground water treatment plant at Huseby, an access tunnel for daily transport is being built in the operating phase, as well as an operating building for, among other things, monitoring the water treatment plant. This should be on the Husebyjordet across the road for Huseby school. In connection with the construction of tunnel and water treatment facilities, Husebyjordet is a rig area, and mass transport and transport of equipment and material are carried out.

In addition to the access tunnel at Husebyjordet, an access tunnel is established at Husebybakken Skipark behind Smestad recycling station. Here there is rig area and transport of masses and other equipment and material during the construction period. When the project is complete, the only visible installation will be a portal, and an access road to the portal.

A new water supply in Oslo must also be built, new water supply tunnels (stem network) must also be built. From Stubberud in Bydel Alna, an 11 kilometer long cleanwater tunnel is built to the planned water treatment plant at Huseby. All masses for this tunnel should be taken out at Stubberud. Emergency pools (50,000 m3) will also be established in Berg east of Trosterud connected to the new tunnels, as well as an escape output at Haugerud, at the parking garage in Haugerudveien

Between Oset at the Maridalsvannet and Disenjordet (Gransjordet) in Bydel Nordre Aker, we build a 3 kilometer long tunnel carried out with conventional drilling and blasting. The main rig area and mass withdrawals will be on the Oset, while there will be a smaller rig area on Disenjordet (Gransjordet). In addition, there will be a connection point between the new and the existing water supply network in Bjølsendumpa in Bydel Sagene.

Project time-line:

Start -up at the construction sites at Husebyjordet, Husebybakken Skipark and Sollerudstranda.
2021-2023

Explosion of access tunnels and mountain halls under Husebyjordet. Explosion of the Solerudtunnel.
2022

Start of rig and construction work at Stubberud and at Oset at the Maridalsvannet.
2023-2026

Drilling of water tunnel between Holsfjorden and Huseby. One tunnel drill started from the Holsfjord in January 2023, the other started from Huseby in March 2023. The machines meet during Lommedalen around the turn of the year 2025/2026.

2023-2027

Drilling of water tunnel that carries drinking water from the water treatment plant under the Husebyskogen and out to Oslo.
2023

Start of rig and construction work on Disenjordet (Gransjordet).
2023-2027

(above information from Oslo Commune information page https://www.oslo.kommune.no/vann-og-avlop/ny-vannforsyning-oslo/slik-bygger-vi-ny-vannforsyning/)