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Type of sights

Natural landmark


Name and address


Immendinger Straße

DE-78532 Tuttlingen


Geodetic coordinates

47.932173 8.763528


657 m


Schematische Karte der Donauversinkung
Schematische Karte der Donauversinkung
Ponor of the Danube sink, near Immendingen
Ponor of the Danube sink, near Immendingen
Das trockene Flussbett der Donau unterhalb von Immendingen
Das trockene Flussbett der Donau unterhalb von Immendingen
Donauversinkung bei Immendingen
Donauversinkung bei Immendingen

The Danube Sinkhole (German: Donauversinkung or Donauversickerung) is an incipient underground stream capture in the Upper Danube Nature Park. Between Immendingen Wikipedia Icon and Möhringen and also near Fridingen Wikipedia Icon (Tuttlingen), the water of the Danube sinks into the riverbed in various places. The main sinkhole is next to a field named Brühl between Immendingen and Möhringen.

The sinking Danube water disappears into a karst water system of the well-stratified limestone formation (the ox2 layer) of the White Jura and appears again in a horizontal limestone layer (the ki4 layer), approximately twelve kilometers away at Aachtopf Wikipedia Icon. It then flows as Radolfzeller Aach into Lake Constance at Radolfzell Wikipedia Icon. Thus, a part of the Danube water also flows into the Rhine. This geographical situation is a striking feature of the large European Watershed, which separates the catchment areas of the North Sea and the Black Sea.

The water flows out through a variety of small to very small cracks and crevices; the karst in these places is apparently at an early stage of development. The cave system of Aachtopf, that is the underground river Danube is, however, probably already well developed.


The first documented case of the Danube completely disappearing into the hole, dates back to 1874. Since then, the number of days per year when this happens, has risen sharply. Between 1884 and 1904, it happened, on average, 80 days per year. In 1922, it happened only on 29 days. In 1923, however, the number increased to 148. Between 1933 and 1937, the average was on 209; from 1938 to 1945, it was 270 days. The highest number so far, was in 1921, with 309 days.


As the karst is developing, future sinkhole stretches are not exactly predictable. The underground river Danube annually removes about 7,000 tons of lime, that is 2,700 cubic meters, from the karst system. Future expansions or collapses in the underground system are conceivable; these would show above ground as sinkholes or ponors.

In the long run today's upper Danube will probably be redirected entirely into Radolfzeller Aach Wikipedia Icon, and thus to the Rhine.

Information about copyright

Rights characteristic / license

by-sa: CREATIVE COMMONS Attribution-ShareAlike

Link to the description of the license

Input taken over from:

Wikipedia contributors, 'Danube Sinkhole', Wikipedia, The Free Encyclopedia, 15 December 2014, 02:57 UTC, <> [accessed 8 January 2015]

taken over / edited on

08 Jan 2015

taken over / edited by