New 8 km underground cloudburst tunnel, Denmark

Following a huge cloudburst in the summer of 2011, municipalities in the Copenhagen area joined forces to work on climate adaptation and established the Copenhagen Cloudburst Programme.

The programme identified the need for several tunnels that can direct cloudburst run-off from the surface and into the Oresund Strait. One of these tunnels, the Svanemøllen Cloudburst Tunnel, will be an 8 km underground bored tunnel with a tunnel diameter of between 1.8 and 3.2 metres. The construction of this tunnel will require state-of-the-art drilling techniques with large tunnel boring machines that will be drilling from deep shafts 15-20 metres below the streets of Copenhagen and surrounding municipalities.

In 2016 COWI was awarded the contract to design this project and for 10 years we will be delivering designs of drainage and tunnel engineering components, hydraulic calculations, environmental impact assessments and general regulatory processing. We will also be responsible for the tender process and construction management.