The Radolfzeller Aach is a right or north tributary of the Rhine in the south of Baden-Württemberg . It is approximately 32 km long.
The source of the river is the Aachtopf in Aach, the largest spring in Germany, at a height of 475 m above sea level. The water emerges from a karst cave. About two thirds of the water originates in the headwaters of the Danube. Between Immendingen and Möhringen an der Donau and in Fridingen, water from the Danube disappears underground ; this water reappears in the Aachtopf.
Copyright: CC 3.0