Freiburg im Breisgau has an unusual system of gutters (called Bächle) that run throughout its centre. These Bächle, once used to provide water to fight fires and feed livestock, are constantly flowing with water diverted from the Dreisam. They were never used for sewage, and such use could lead to harsh penalties, even in the Middle Ages. During the summer, the running water provides natural cooling of the air, and offers a pleasant gurgling sound. It is said that if you fall or step accidentally into a Bächle, you will marry a Freiburger, or 'Bobbele'.

"Venice for your feet"

—Klaus Eberhartinger 2010 at a concert

"On the longs walks through the traffic-free city center one crosses a channel carelessly - and suddenly a little boat made out of paper is floating by. Children are playing in the water in the middle of the business center of a city. [...] Fresh water from the Black Forest is briskly flowing next to the streets, taking with it the dust and cleaning the air. At least this is the argument when people from the north complain about the absurd and dangerous mantraps. Of course one wants to respond with something that gives an illusion of practical use. But I think, the Bächle are less for cleanliness than for the soul."

—Ruth Merten in Wenn Freiburgs Blüten blüh'n, 1986