European Watershed Danube–Rhine

The Rhine-Danube watershed cuts through southern Germany. In a north-easterly direction, it runs through the federal states of Baden-Württemberg and Bavaria as well as part of the Alps in Austria and Switzerland. The Rhine-Danube watershed has a special feature due to the seepage of the Danube near Immendingen: a large part of the water that seeps away there overcomes the watershed underground and emerges again after about twelve kilometers in the Aachtopf. As a result, part of the Danube water flows over the Radolfzeller Aach, which rises from the Aachtopf, into Lake Constance and thus flows into the Rhine.

The European watershed between the Danube and the Rhine can be found on the information board

The watershed is marked in the area in several places, including here