With World Water Day on 22 March, the United Nations (UN) annually reminds us of the importance of water as the most essential resource for all life. As we all know, this resource is becoming increasingly unbalanced due to climate change. Extreme droughts followed by heavy rainfall - such weather events are also becoming common in Germany.
That is why the city of Berlin now wants to create a sponge-like effect that literally absorbs water mass. Sponge city is the name of the corresponding urban planning concept: In a sponge city, rainwater is stored where it falls, cleaned by the soil, and returned to the hydrological cycle and groundwater through evaporation and infiltration.
Siemensstadt Square also follows this future model in urban development. Planned, built, and operated with the environment in mind, this new Berlin district is committed to the careful use of materials and raw materials, opting for a forward-looking and recyclable approach to the problem. The planning team for Siemensstadt Square is committed to an all-encompassing concept, making every street, every building, and every open space a contributing factor for rainwater management in the future.
Designed as a sponge city, Siemensstadt Square will not simply drain rainwater into the sewage system, but rather use it as a valuable resource. The rainwater seeps away and evaporates via green spaces and roofs, creating a good urban climate and feeding the local groundwater. Rainwater utilisation for buildings and irrigation should help relieve the burden on the sewage system and save valuable drinking water.
The cascade solution for rainwater management demonstrates the principle of the sponge city on a small scale: green roofs delay rain runoff and evaporate part of the precipitation. Slowly, the rainwater is channeled into courtyards and open spaces, where it feeds the vegetation and is finally collected in cisterns. During heavy rainfall, rainwater retention basins collect the water to prevent flooding and create storage for later use.
In this way, Siemensstadt Square becomes a ‘storage city’ and hence a working example of how intelligent rainwater management not only improves life in the city, but also becomes an effective tool against climate change.