potsdamer platz, berlin
Atelier Dreiseitl

Completed in 1998, the waterscape project at Potsdamer Platz has contributed to making Potsdamer Platz one of the most visited places in Berlin. During the first half of the 20th century, Potsdamer Platz was an important square and intersection in Berlin. In World War II it was completely destroyed by bombings and later divided in the 1960s by the Berlin Wall. When the Wall came down in 1989, the redevelopment of the empty Potsdamer Platz provided one of the largest building sites in Europe. As an office, entertainment and shopping development, the area today holds the headquarters for multinational corporations like Sony and Daimler Chrysler, along with theaters and a large mall.

design concept
The challenge for Atelier Dreiseitl was to provide an "oasis of calm and beauty" in a highly constricted downtown site where people could relax and gather outside of the commercial areas. As Dreiseitl writes, "What devices for planning open space, 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?" (44)

Creating a waterscape allowed the design team a response to the above questions: they used water as a central design principle for the open space and met high ecological standards through an integrated rainwater management system.

"East meets West -
the Potsdamer Platz is a place of healing old divides." (Dreiseitl)

The waterscape design for Potsdamer Platz metaphorically bridges the old divide between East and West Berlin by providing multiple opportunities for people to cross over and interact with the water. Water flows down an impossibly slight slope from a large main pool into a piazza where shallow flow-steps create a shimmering surface of rhythmic waves. People can rest along the pool's edges or criss-cross its banks on stepping stones that lead over the expanse of water. Adjacent to the piazza, water drifts over wave cascades and emerges in a narrow channel. The overall effect of water in Potsdamer Platz is an "interplay of wind, nature and art [that] produces visual color games." (Dreiseitl 48).

stormwater management  
At Potsdamer Platz, a combination of green and non-green roofs harvest the 21 inches of annual rainfall. This rainwater then flows down through the site's buildings and is used for toilet flushing, irrigation and fire systems. Excess water flows into the pools and canals of the outdoor waterscape. To accommodate large rainfalls, there are five underground cisterns for storage. Slowly, this water is fed into a succession of narrow pools and a larger main area of water on the southern side of the site. Planted purification biotopes are integrated as a part of the overland landscape and serve to filter and circulate the water that runs along streets and walkways (Dreiseitl 46).

More technical details can be found here.