Danube Sinkhole

The Donauversinkung (also Donauversickerung ) is an underground incomplete Flussanzapfung in the Upper Danube Nature Park. Between Immendingen and Möhringen and Fridingen ( Landkreis Tuttlingen ) sinking waters of the Danube area at various points in the river bed. The Hauptversinkungsstelle is located at Won Brühl between Immendingen and Möhringen.

The term Versinkung is preferred because the water does not spread in the soil ( seeps ), but flows in underground cavities.

Hydrographic

The sinking Danube water disappears into a karst water system of well- Layered limestone formation of the White Jura ( ox2 ) and enters verschwammten lying Bankkalken the White Jura (ki 4) in approximately twelve kilometers away Aachtopf again. It then flows as Radolfzell Aach at Radolfzell in Lake Constance. Thus, a part of the Danube water also flows into the Rhine. This geographical situation is a striking feature of the great European watershed which separates the basins of the North Sea and the Black Sea.

The water flows through a variety of small to extremely small cracks and crevices; karstification located at these sites so still at an early stage of development. The cave system until Aachtopf, so the underground Danube is, he probably has already developed far. The results from the close correlation of the water temperatures of the Danube and Aachquelle, which suggests rather an underground river as a ramified system of clefts.

In the 1960s, Jochen Hasenmayer has the Aachtopf from the first 400 m of a large, damp cave -like source, the Aach cave, discovered and explored.

History

The first testified full Versinkung occurred in 1874. Since the number of Versinkungstage per year has risen sharply. While measurements from 1884 to 1904 revealed 80 Vollversinkungstage annually, in 1922 only 29 days were measured, 1923 were then again 148 days, from 1933 to 1937 the number of which increased to 209 days and from 1938 to 1945 to 270 days. A record rendered the year 1921 with 309 Versinkungstagen.

The proof of the link between Donauversinkung and Aachtopf succeeded on 9 October 1877, when the geologist Adolf Knop from the Technical University of Karlsruhe offset the water in the Donauversinkung with 10 kg of sodium fluorescein, 20 tons of salt and 1200 kg shale oil. After 60 hours, all three substances were detected in Aachtopf, which manifested itself in " gloriously green lit" salt water with significantly kreosotartigem taste. Later, the connection of individual Versinkungsstellen was explored. Thus, a shaft was about 1908 in Fridingen applied to find out by experiment, where the water flows out of this Versinkung.

In 1927, on the other hand brought before the State Court of the German Reich a between countries Württemberg and Prussia as ruler of the Hohenzollern land on the one hand and the state of Baden -simmering dispute over the quantitative impairment of the Danube water, which became known as Donauversinkungsfall.

View

How karstification will develop in the future to the Versinkungsstrecken is not exactly predictable. The underground Danube carries about 7,000 tons ( 2,700 m³ ) Lime from the karst system of Aach pot from annually. Are conceivable in the near future expansions or collapses in underground system, above ground recognized by sinkholes or new Ponoren ( sip holes ).

In the long run, the Todays Top Danube is redirected probably completely to Radolfzell Aach, and thus to the river system of the Rhine out. Then the now insignificant tributaries Krähenbach would ( in Möhringen ) and Elta ( Tuttlingen ) to the new source rivers of the Upper Danube, which, however, already less water than that joins the road leads Iller. Perhaps a similar Flussanzapfung has the ancient Danube ( in this section Feldberg- called Danube ) in the Würm even further upstream, at the present Wutach knee in Blumberg, experienced.

Interventions

A bypass the seepage occurs over several studs. In Fridingen Danube and Bara drive to a hydroelectric power plant. The water diversion of the weir is done, bypassing the approximately eleven kilometers Friedinger Danube loop, together with the local Versinkungsstelle by a 1.4 km long tunnel at the eastern end of the tunnel of the Danube Valley Railway (48 ° 2 ' 9.47 " N, 8 ° 57' 24, 39 " O48.0359638.956774 ).

Documentation

• The Black Danube: A River disappears. Documentation directed by Axel Nixdorf ZDF under cooperation with ARTE, Exciting times Filmproduktion GmbH, 50 Minutes, Germany, 2009. German Original Air Date 29 April 2010 on ARTE.