© Adobe Stock - Markus Keller

In the Donaubergland - from the Danube valley to the source of the Aach

The fascination of Danube infiltration

The battle for water

© Donaubergland Tourismus GmbH

Welcome to the Donaubergland

Off into two oceans

The second largest river in Europe "disappears" underground right after its source.

The Danube is a strange river, especially on its first stretch.

At first you can argue about where exactly it has its source, and as soon as it has found its way past Donaueschingen, it does something unique in the world: it splits and flows into two (world) seas.

At Immendingen and Möhringen, a large part of the Danube water simply sinks into swallow holes. There are further sinkholes and seepage points as far as Fridingen. What flows off above ground will eventually flow into the Black Sea on a journey of around 2800 kilometers.

However, what disappears and flows underground finds its way south and reappears after two or three days at the source of the Aach in Hegau. From there, the Danube water flows via the Radolfzeller Aach into Lake Constance and the Rhine, and with the Rhine into the North Sea.

More and more frequently, the riverbed is completely dry in summer, now around 200 days a year. Then the Danube goes completely underground. Then it is said that 'Vienna lies on the Krähenbach', the first tributary after the seepage point, which flows into the Danube bed at Möhringen.

Why is that so?

Because the limestone of the Swabian Alb, which the Danube meets at Immendingen coming from the Black Forest, is becoming increasingly porous. And because the Rhine is literally draining the Danube in the long term, as the Rhine ditch is deeper and the water prefers to flow in this direction.

Source of knowledge

The Danube

Is it true that Vienna and Cologne are both on the same river?

The Danube is the only river in the world to flow into two oceans, the Black Sea and the North Sea.

Danube & Rhine

Which of the two will win in the end?

A unique spectacle of river history is taking place in the Swabian Alb. This battle of the giants has been going on for millions of years. The loser has long been clear: the lower-lying Rhine is taking the Danube's water.

The Rhine

Why can it take the Danube's water?

The Rhine water system was formed later than the Danube system and is deeper. As the limestone in the (Swabian) Jurassic rock is highly water-soluble and brittle, deep cracks, crevices and caves form in which the Danube water can sink.


What are the consequences of the Danube infiltration for the town?

For decades, the "weakening" Danube in Tuttlingen was dammed up into a stately, rather stagnant body of water in order to be able to use it economically. Under today's conditions, weirs are to be removed as barriers. What remains is a low watercourse.


Why did the people of Baden and Württemberg fight over the Danube water?

Immendingen, Möhringen and Aach in Hegau used to be Baden, while Tuttlingen, Mühlheim and Fridingen were Württemberg. If the water in "Baden" disappears more and more and flows away, then it increasingly disappears as water power for the economy.

Climate change

What effect does this have on Danube infiltration?

On the one hand, the rivers are carrying less and less water, which means that less and less flows over the sinking points. On the other hand, heavy rainfall is leading to more frequent short-term flooding.

Fascinating places

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