There's the so-called 'Blautopf', the origin of the 22 km long river 'Blau' on the southern edge of the Swabian Alb, located at Blaubeuren, Baden-Württemberg, Germany.
Even less than 300 meters according to their origin in 'Blautopf' the 'Blau' flowing from the southwestern part of the valley first through 'Blaubeuren' and it's district 'Gerhausen'. Then it enters the municipal area of ??'Blaustein' and successively passes the village 'Arnegg' on the right foot of the slope, the village 'Herrlingen' on the left and 'Klingenstein' in the right pastures on the local slope. Then she returns to East, run and passes 'Ehrenstein' which extends to the opposite slope to 'Klingenstein'.
In Ulm it flows the industrial area and the blue channel in 'Blue Park' where it then divides into two branches, 'Kleine Blau' and 'Große Blau'. As the centerpiece of the 'Kleine Blau' the project had to give way in the area of ??the main station City Station, it will be undertaken through a channel in the 'Große Blau', thereafter performs under the main station in Ulm. After the main station 'Kleine Blau' and 'Große Blau' branch again and flow through the fishing districtat for a distance of a few meters. The 'Kleine Blau' is finally reinitiated in the 'Große Blau', which opens into the Danube.
source: [DE] Wikipedia