How much rain seeps into the ground in the Tiergarten? How much evaporates from the Tempelhofer Feld? And how much ends up in the sewer system at Potsdamer Platz? These are some of the questions explored in this topic. It combines data from the DWD (Germany’s National Meteorological Service) and the BWB (Berlin’s water supply and wastewater treatment company) with detailed knowledge of local site conditions. For example, far more water infiltrates into the soil and evaporates in a park than on a paved parking lot.
Effective water management in a major city requires an understanding of where water infiltrates into the ground and where groundwater is recharged. To investigate this in detail, the city was divided into 25,000 individual areas. Using the Berlin Water Balance Model (ABIMO), six years of data were simulated to determine the long-term average fate of rainfall in the area.
Overall, nearly two-thirds of Berlin’s rainfall returns to the atmosphere through evaporation. Of the remaining amount, about two-thirds seeps into the ground, while the rest flows into the sewer system.
Berlin residents can also play a role in improving the city’s water balance. Green roofs, for example, encourage evapotranspiration by holding rainwater and preventing it from entering gutters and the sewer system. Their impact was included in the model starting in 2017.
The maps presented here for 2022 form part of the results from the AMAREX research project (AMAREX is the acronym for the German translation of ‘adaptation of stormwater management to extreme events’). This joint project is funded by the Federal Ministry of Research, Technology and Space (BMFTR) within the hydrological extreme events (WaX) funding programme (funding reference: 02WEE1624A-H). The initiative operates under the umbrella of the federal water programme Wasser: N and is part of the BMFTR’s Research for Sustainability Strategy (FONA).
