What 15 km river, located in southern Germany, whose name means "Blue Pot" flows east through Blaustein to the city of Ulm?
Blau (Danube) The Blau (] ) is a 15 km long river in Baden-Württemberg, southern Germany, and a left tributary of the Danube. The source of the Blau is the karst spring of "Blautopf", in the town Blaubeuren, in the Swabian Jura. It flows east through Blaustein to the city of Ulm, where it empties into the Danube.
Ablach (Danube) The Ablach is a right tributary of the Danube. It rises on the European Watershed, which is only a hint in this area, from the Mindersdorfer Aach in the municipality of Hohenfels in the Landkreis of Konstanz. It is about 36 km long, or, when including the headwaters in the Hohenfels area, 38 km .