Dreisam

The Dreisam (German pronunciation: [ˈdʁaɪzaːm]; Celtic: *tragisamā, "the very fast one") is a 29 km long river (48.8 km including its source river Rotbach), and a tributary of the Elz in the German state of Baden-Württemberg. The waters of the Dreisam feed the famous Freiburg Bächle runnels.

Source: Wikipedia https://en.wikipedia.org/wiki/Dreisam