Blau River: The Karst-Fed Tributary of the Danube
Flowing through the scenic landscapes of southern Germany, the Blau is a significant river in the state of Baden-Württemberg. Known for its striking origins and its role in the regional geography, this 22.2-kilometre waterway serves as a vital left tributary to the Danube, connecting the highlands of the Swabian Jura to the urban center of Ulm.
Key Facts
- Length: 22.2 km (13.8 mi)
- Source: Blautopf karst spring in Blaubeuren
- Mouth: The Danube river in Ulm
- Basin Size: 499 km² (193 sq mi)
- Location: Baden-Württemberg, Germany
The Journey of the Blau
The river begins its journey at the Blautopf, a renowned karst spring located in the town of Blaubeuren. A karst spring is a point where groundwater emerges from soluble rocks, such as limestone, creating clear and often deep pools. From this dramatic start in the Swabian Jura, the Blau flows eastward.
As it progresses, the river passes through the municipality of Blaustein before reaching the city of Ulm. In Ulm, the Blau completes its course by emptying into the Danube, contributing its waters to the larger river system that eventually flows into the Black Sea.
Geological History of the Blau Valley
The landscape through which the Blau flows was not originally shaped by the river itself, but by the Danube. In a prehistoric geological shift, the Danube initially carved a deep valley into the region. However, as the Swabian Jura rose, the Danube shifted its course toward the southwest.
This shift left behind a valley that was later occupied by other waterways. While the Schmiech river now flows south to meet the Danube in Ehingen (Donau), the Blau took an eastward path toward Ulm, utilizing the ancient valley carved by its larger counterpart.
River Specifications
| Feature | Detail |
|---|---|
| Total Length | 22.2 km (13.8 mi) |
| Drainage Basin | 499 km² (193 sq mi) |
| Source Location | Blaubeuren (Blautopf) |
| Mouth Location | Ulm (Danube) |
| Coordinates of Mouth | 48°22′48″N 9°47′10″E |
Frequently Asked Questions
Where does the Blau river start?
The Blau originates from the Blautopf, a karst spring located in the town of Blaubeuren within the Swabian Jura.
Where does the Blau river end?
The river flows east and empties into the Danube in the city of Ulm.
How long is the Blau river?
The river has a total length of 22.2 kilometres (approximately 13.8 miles).
How was the Blau valley formed?
The valley was originally incised by the Danube river before the Danube changed its course to the southwest during the rise of the Swabian Jura.
What is the total size of the Blau's basin?
The basin size of the Blau is 499 square kilometres (193 square miles).