The costs for the cloudburst in Copenhagen in July 2011 have been estimated to close to 1 billion Euros. To avoid such damages, and associated costs, most cities have to be redesigned with regards to the possibility to store large amounts of stormwater. The challenge and innovation lies in the type of storage that you can provide. Surface storage of stormwater requires space, which is hard to achieve in dense urban areas, and which also cost a lot of money in terms of unsold properties. Accordingly, especially in dense urban areas, there is a need for space-efficient stormwater storage. To achieve this, in many cases combinations of surface and underground solutions will be needed.