Boring of the Flood Tunnel Under Frederiksberg and Vesterbro is finished

The giant drilling machine "Sigrid" of 110 tonnes has just drilled the second and last part of Kalvebod Brygge Flood Tunnel, which is an important part of keeping Eastern Frederiksberg and Vesterbro free of flooding in the event of a flood. However, the flood tunnel is only expected to be ready for use in 2026, and a number of other projects are waiting in the neighborhood.

For the past three months, Sigrid has drilled 702 meters through the underground from Kalvebod Brygge and up to Halmtorvet in Copenhagen. This has happened as part of the construction of the 1.3 -kilometer Kalvebod Brygge Flood Tunnel, which runs from Gammel Kongevej to Kalvebod Brygge and forms and a central part of the flood protection of eastern Frederiksberg and Vesterbro.

Shortly before Christmas, Sigrid was baptized at a drilling shaft at Kalvebod Brygge - for claps from project people from the contractors NCC and SMET as well as the builders Frederiksberg Forsyning and HOFOR, the metropolitan area's utilities, and advisers from NIRAS.

New teeth along the way
Since the turn of the year, Sigrid has completed her demanding journey towards Halmtorvet about 18-20 meters down in the underground, where she has passed under roads, railroad tracks and the entire meat town as well as very close to the metro line. Along the way, she has changed her teeth and other spare parts nine times. This has happened with the help of business divers who have worked under pressure inside the bore head to keep the surrounding groundwater out.

- The name Sigrid, which originates from the Viking Age, means "victorious beauty", and that name she has lived up to her important journey to that extent. Sigrid - and the team behind - have delivered a crucial victory in the fight to protect the city from flooding after flood and massive rain in the future. But climate change gives more water than we can imagine, so while this tunnel can accommodate all the flood water that was in Istedgade after the 2011 flood, more solutions are needed if the city is to work when it rains so strongly, ”says Managing Director Henrik Plougmann Olsen from HOFOR.

Protects values
The importance of flood tunnel for both Copenhagen and Frederiksberg was reflected in the speakers at Sigrid's arrival at Halmtorvet:

- We owe Sigrid and the whole team behind a big thank you. Because when Kalvebod Brygge Flood Tunnel is finally ready in 2026, it will have a great impact on the city's citizens and users, especially people in eastern Frederiksberg and Vesterbro. It protects values and creates increased security because it helps to make the areas robust to cloudbursts, said Henrik Bay, CEO of Frederiksberg Forsyning.

Still many tasks
The contractors, who together with Sigrid have done the tunnel drilling work, were also pleased with the well -done drilling work:

- Drilling a tunnel on a stretch of so much complexity is a demanding task that we are happy and proud to have resolved with our Belgian partner Smet. Now we look forward to solving the next tasks, namely the connection of sewage overflows, the closure of the large work shafts and the processing to the pumping station at Kalvebod Brygge, said Bjarki Finnbogason, area director at NCC.

Space for the rainwater in the city
Kalvebod Brygge Flood Tunnel is an important piece in the hundreds of solutions to secure Frederiksberg and Copenhagen against flooding due to cloudbursts and heavy rain. The tunnel, which is up to three meters in diameter, can in itself store 10,000 cubic meters of water, which is equivalent to water at a meter in height through Istedgade. Excess water from the sewers can thus wait in the tunnel pipe until there is space on the wastewater treatment plant, so that in the vast majority of rainfall, the water is avoided into the harbor.

20 cubic meters of water per second
Only in the most extreme flood cases will the water be pumped up from the tunnel and directly into the harbor via a pumping station at Kalvebod Brygge. In that case, it will happen below the water surface and at a speed of 20 cubic meters of water per second. And this will only happen to avoid the same water pushing up the streets and flooding both eastern Frederiksberg and Vesterbro, as it happened in 2011.

Before the tunnel is put into use, the utilities expect to be able to show the tunnel very close.

Fact box:

• Kalvebod Brygge Flood Tunnel becomes 1.3 kilometers long and must be finished in 2026
• The tunnel pipes run 18-20 meters down into the ground and have an interior diameter of up to 3 meters
• The tunnel itself can store 10,000 m3 of flood water, corresponding to filling the entire Istedgade with water at almost one meter altitude. When there is space again at the treatment plant, it can be pumped on. This avoids in most flood situations to lead water out into the harbor
• The tunnel and an associated pumping station at Kalvebod Brygge can lead 20 cubic meters of water away from the city - per second.
• The first stage of Kalvebod Brygge Skybrudstunnel was drilled by the machine "Signe" in the first half of 2023 - on the stretch from Gammel Kongevej to Halmtorvet (a total of 535 metres).
• HOFOR, the capital city's utility company, and Frederiksberg Forsyning are building the tunnel
• NCC/SMET is the contractor on the project
• Niras is an advisor on the project

https://via.ritzau.dk/pressemeddelelse/13817617/skybrudstunnel-under-frederiksberg-og-vesterbro-er-boret-faerdig?publisherId=13561759&lang=da