Aachtopf

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Aachtopf
AachTopfPano02.jpg
Aachtopf
location
Country or region District of Constance ( Baden-Württemberg )
Coordinates 47 ° 50 ′ 48 "  N , 8 ° 51 ′ 29"  E
Aachtopf (Baden-Württemberg)
Aachtopf
Aachtopf
Location of the source
geology
Mountains Hegau
Source type Karst spring
Exit type Source pot
Hydrology
River system Rhine
Receiving waters Radolfzeller Aach → Rhine → North Sea
Bulk 8590 l / s
depth 18 m

Coordinates: 47 ° 50 ′ 48 ″  N , 8 ° 51 ′ 29 ″  E

The Aachtopf (also Aachquelle ) near Aach in Baden-Württemberg is the most water-rich spring in Germany. The Radolfzeller Aach (also Hegauer Aach ) rises from the karst spring and flows into Lake Constance after 32 km near Radolfzell .

Data

The spring has an average discharge of 8,600 l / s; However, as is usual with karst springs, this is strongly dependent on the season and fluctuates between 1,300 and 24,000 l / s. The water of the Aach spring rises from an 18 m deep underground spring cave and forms a small lake.

Water origin

Map of the upper course of the Danube with the sinking of the Danube
Main sinking point of the Danube below Immendingen
View from the source pot in the direction of the river

The water in the karst spring comes mainly from the Danube, which sinks between Immendingen and Möhringen and near Fridingen . The catchment area includes other drainage holes from other rivers, e.g. B. at Neuhausen ob Eck and at Heudorf im Hegau . About a third of the pouring of the Aachquelle is due to such secondary tributaries.

From the sinking of the Danube, the water flows underground about 12 km at a speed of about 200 m / h through cavities to the Aachtopf.

On the approximately 130 days of full infiltration, the upper Danube thus belongs entirely to the river system of the Rhine . With further dissolution of the limestone until the collapse of the caves, a process similar to the Wutach diversion could take place in the future , at the end of which the upper course of the Danube becomes a tributary of the Rhine.

Surroundings

There are other small springs on the banks of the Aach and below the Aachtopf in the river bed. The southernmost proven outlet of the Danube water is the bleaching spring near Singen . The Aachtopf is a popular destination.

From the Middle Ages to around 1950, water power was used by numerous mills. Since 1935/36 the water has been led to an electricity company in a canal. Due to the use of water, both on the Württemberg Danube and the Baden Aach, there were repeated disputes about water: the drainage holes on the Danube were repeatedly blocked, or the water was dammed up above the sink holes. ( See: Danube sinking case ). A common solution could only be found after the state of Baden-Württemberg was founded.

exploration

In 1719 the assumption that the spring water came from the sinking of the Danube was first expressed in a publication by FW Breuninger. However, evidence was only found on October 9, 1877, when the geologist Adolf Knop from the Technical University of Karlsruhe added 10 kg of sodium fluorescein , 20 t of salt and 1200 kg of shale oil to the water in the Danube sinkhole . After 60 hours, all three substances could be detected in the spring pot, which was expressed by the splendidly glowing green salt water with a distinctly creosote-like taste.

In 1886 there was the first attempt to dive to a depth of 12 m (one of the world's first attempts to dive into a cave ), where the difficult-to-overcome nozzle is located, a narrow point in which the water has a strong current.

The spring cave was explored by Jochen Hasenmayer from the 1960s . A hall with a sinter basin and stalactite remains were discovered, which shows that this hall was once an air-filled creek cave. In the years from 1980 onwards, the Aach cave was intensively researched by Harald Schetter. Jürgen Bohnert, Frank Liedtke, Stephan Liedtke and Tobias Schmidt have been measuring the Aach cave since 2001. After 500 m to the north, the cave ends in a massive fall, which can also be seen on the surface as a large sinkhole in the forest. After 14 years of excavation, the continuation of the Aach cave was discovered on the northern edge of the sinkhole. Since the chemical composition of the water here does not match that of the Aachhöhle, it is assumed that it must be one of several feeders. Therefore the cave is called the Danube Cave from here on .

In April 2017, the first discovery of a cave fish in Europe was announced. It is a largely pigmentless and probably blind population of the common loach ( Barbatula barbatula ). It was discovered in the branching cave system of the Aachtopf, but is likely to occur in the entire 250 square kilometer cave system up to the sinking of the Danube .

See also

Web links

Commons : Aachtopf  - collection of images, videos and audio files

Individual evidence

  1. ↑ A. Knop: About the hydrographic relationships between the Danube and the Aach spring in the Baden Oberland. In: New Year Mineral. Geol. Palaeontol 1878. pp. 350-363.
  2. ^ H. Hötzl: Origin of the Danube-Aach system. In: Environmental Geology. Volume 27, No. 2, 1996, pp. 87-96. doi: 10.1007 / BF01061676
  3. ↑ Jasminca Behrmann-Godel, Arne W. Nolte, Joachim Kreiselmaier, Roland Berka, Jörg Freyhof: The first European cave fish. In: Current Biology. Volume 27, Issue 7, April 3, 2017, pp. R257 – R258. doi: 10.1016 / j.cub.2017.02.048