For 150 years, combined sewer systems have been crucial for maintaining hygiene standards in cities and protecting properties from flooding. However, during periods of heavy rainfall, these systems can become overloaded and result in combined sewer overflow into surface waters, severely impacting water quality and leading to fish deaths and excessive algae growth.
To mitigate these effects, underground storage spaces have been introduced in recent years to capture unusually large amounts of water and reduce the frequency of combined sewer overflows into surface waters. Unfortunately, the current storage volume of 300,000 cubic meters is still insufficient to cope with sudden increases in water volumes during heavy rainfall. To address this issue, Berlin aims to disconnect one percent of the sealed urban area from the combined sewer system annually to reduce the inflow of rainwater into the sewer system.
KWB has been working on this issue for years and supports decision-makers and administrations in the strategic planning of disconnection measures. The MiSa project, commissioned by the Berlin Senate Department for Mobility, Transport, Climate Protection and the Environment, is another milestone in this effort. MiSa develops the conceptual basis to support the Senate in further developing a combined sewer remediation program. A digital tool will simulate the possibilities of disconnecting previously connected urban areas from the combined sewer system and the effects on the sewer and water systems.
The project is carried out in cooperation with Ingenieurbüro für Wasser und Umwelt, Berliner Wasserbetriebe, Berliner Regenwasseragentur, and the districts of Friedrichshain-Kreuzberg and Charlottenburg-Wilmersdorf. MiSa will bring all partner institutions together to develop realistic scenarios, providing a great opportunity to discuss Berlin’s integrated goals for climate adaptation and environmental justice, especially in times of limited resources.
Disconnection measures can be planned much more effectively and efficiently with MiSa. This will bring Berlin closer to its ambitious disconnection goal and will also make a significant contribution to environmental and water protection.