Less flooding and more blue-green recreational areas. This is the ambition for the cloudburst mitigation plans in the Danish capital. The innovative plans provide a view into the future for cities around the world.

The Danish capital’s cloudburst mitigation plans are focused on solving increased heavy rain challenges, climate adaptation of the sewerage systems, as well as creating higher living standards in the city that will benefit the residents.

In 2011 ,Copenhagen experienced the worst and most destructive cloudburst in the city’s history. Water poured into basements and stock rooms, resulting in damages of approximately EUR 1 billion. The city has since then invested heavily in safeguarding against future extreme weather, while at the same time exploiting positive aspects of the restructuring to turn the problem into a resource; a blue-green city with more urban quality and increased biodiversity.

This is the most ambitious and comprehensive roll-out of safeguards against cloudbursts in Denmark, and Copenhagen’s mitigation plans show how entire neighbourhoods can be protected from the heavy rainfalls that are an inevitable part of the future. The innovative plans are already attracting international attention from, for example, USA and Asia.

End-to-end solutions

Ramboll has managed the process and the preparation of solutions to mitigate the effects of cloudbursts at project design level and has created end-to-end solutions that will add as much value as possible for citizens and the municipalities.

Specifically, the proposal consists of both green and blue surfaces, that retain rainwater locally, and the establishment of so-called cloudburst boulevards – which quickly and effectively directs water out of the city, while taking into account traffic and urban quality. This is necessary in the case of heavy downpours, where green surfaces are not enough. The cloudburst boulevards are supplemented with cloudburst pipelines to handle separate rainwater.

Multidisciplinary Team of Experts

Ramboll has been part of a multidisciplinary team of experts within project management, storm water management, hydraulic calculations, landscape architecture, urban development, traffic, nature, and socio-economic assessments. Ramboll prepared the plans together with the internationally renowned landscape architectural company (now a part of Ramboll) Atelier Dreisetl.