The Blau () is a

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

Baden-Württemberg Baden-Württemberg (; ), commonly shortened to BW or BaWü, is a German state () in Southwest Germany, east of the Rhine, which forms the southern part of Germany's western border with France. With more than 11.07 million inhabitants across a ...

, southern

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

, and a left tributary of the

Danube The Danube ( ; ) is a river that was once a long-standing frontier of the Roman Empire and today connects 10 European countries, running through their territories or being a border. Originating in Germany, the Danube flows southeast for , pa ...

. The source of the Blau is the

karst spring A karst spring or karstic spring is a spring (outflow of groundwater) that is part of a karst hydrological system. Description Because of their often conical or inverted bowl shape, karst springs are also known in German-speaking lands as a ''Top ...

of ''

Blautopf The Blautopf (German for ''Blue pot'') is a spring that serves as the source of the river Blau in the karst landscape on the Swabian Jura's southern edge. It is located in Blaubeuren, Alb-Donau-Kreis, Baden-Württemberg, Germany (approximately w ...

'', in the town

Blaubeuren Blaubeuren () is a town in the district of Alb-Donau near Ulm in Baden-Württemberg, Germany. it had 11,963 inhabitants. Geography Geographical location The core city Blaubeuren lies at the foot of the Swabian Jura, west of Ulm. Neighboring ...

, in the

Swabian Jura The Swabian Jura (german: Schwäbische Alb , more rarely ), sometimes also named Swabian Alps in English, is a mountain range in Baden-Württemberg, Germany, extending from southwest to northeast and in width. It is named after the region of ...

. It flows east through

Blaustein Blaustein () is a town in the district of Alb-Donau Baden-Württemberg in Germany. It is situated on the Blau River, 6 km west of Ulm and has about 15,000 inhabitants. Before 1968, Blaustein was known as Herrlingen. It was created in 196 ...

to the city of

Ulm Ulm () is a city in the German state of Baden-Württemberg, situated on the river Danube on the border with Bavaria. The city, which has an estimated population of more than 126,000 (2018), forms an urban district of its own (german: link=no, ...

, where it empties into the

Blau valley

The valley of the Blau was formed by the Danube. When the Swabian Jura rose, the Danube initially incised a deeper and deeper valley but finally chose a course to the southwest. In the valley it left behind today, the

Schmiech Schmiech is a small river in the Swabian Alb, Baden-Württemberg, Germany. Its source is a karst spring. It flows into the Danube in Ehingen. See also *List of rivers of Baden-Württemberg A list of rivers of Baden-Württemberg, Germany: A ...

river flows south meeting the Danube in

Ehingen (Donau) Ehingen (Donau) (; Swabian: ''Eegne'') is a town in the Alb-Donau district in Baden-Württemberg, Germany, situated on the left bank of the Danube, approx. southwest of Ulm and southeast of Stuttgart. The city, like the entire district of ...

, whereas the Blau flows east towards

References

Rivers of Baden-Württemberg Rivers of Germany {{BadenWürttemberg-river-stub