City of Winterthur (CH), Wastewater storage basin Dättnau
The sewerage network of the city of Winterthur consists of over 600 km of private and public sewerage. It collects wastewater from Winterthur and 11 surrounding municipalities and directs it to the ARA Hard. During heavy rainfall, the sewerage system below the Dättnau stormwaterbasin was overloaded even though the Dättnau stormwater basin above was almost never filled.