Sustainable Cities™

Berlin: Water creates a vibrant cityscape

On Potsdamer Platz in Berlin, Germany, the aesthetic qualities of water have been exploited most successfully – without wasting a single drop. The Urban Waterscape scheme combines rainwater harvesting with a recreational cityscape and demonstrates how recycling rainwater can be of benefit to the cities of the future affected by climate change. The idea is that rain falling on the square will be used on the spot.

Model over regnvandsopsamlingen på Potsdamer Platz., illustration: Atelier Dreiseitl ©

Rain falling on Potsdamer Platz becomes the water table and a canal installation in the open cityscape which has helped to make the square one of Berlin's greatest tourist attractions. In this way, a recreational cityscape has been combined with environment friendly planning. A co-benefit of this is that water use and environmental issues become topical for the city's citizens and its visitors.

A little more than half of the harvested rainwater is used for irrigation, the pools and canals in the area, while the rest is used in the buildings to flush lavatories and by fire extinguishing systems. Five massive underground cisterns accommodate the excess water in the event of extremely heavy rainfall. From here, the water is fed into the system of canals built on the south side of the building complex. Integrated into the system are biotopes, plants with a cleansing effect which filter the water as it passes through them.

Potsdamer Platz, courtesy of Atelier Dreiseitl

'Urban Waterscape', designed by Atelier Dreiseitl, came into being, like many other "green" solutions in central Berlin, as a result of both opinion and sheer necessity. With so much building being done, neither the supply companies nor the infrastructure would be able to keep up without a good deal of new thinking.

"Which devices are necessary when planning open spaces, what themes can be used to do justice to a lot of people and the urban design at the same time, and finally to come close to meeting ecological aims?"Atelier Dreiseitl

The idea behind the Urban Waterscape is that the rainwater should be used where it falls. This is achieved by collecting approximately 23,000 m³ of rain water a year from the roofs of the 19 buildings in the area. About 60% of the roof space is covered with grass, so that some of the rainwater evaporates while the rest is stored. Another benefit of the green rooms is that the temperature in the buildings is reduced during the summer, thus saving energy that would otherwise be spent on cooling.

Climate change will cause periodically heavier rainfall and as a result, the sewers of the cities will become overloaded, increasing the risk of freshwater becoming polluted. During reconstruction of Potsdamer Platz they also had to take into consideration that the soil in the area was not able to absorb such large quantities of precipitation. It was therefore necessary to develop new, efficient and environmentally sustainable solutions.

Last updated Tuesday, January 21, 2014