English: Calctuff runnel (Steinerne Rinne) southwest of the village Dießen (west of Horb am Neckar), Baden-Württemberg. When attempts were made to drain a wet meadow ca. three hundred years ago, a calctuff runnel began to develop. The legally protected, fragile runnel monument at Dießen has a length of ca. 200m. The geology of the area is mainly Muschelkalk (Triasssic).
The valley of the rivulet Dießen is the „Naturschutzgebiet Dießener Tal und Seitentäler“. Different kinds of calctuff depositions are quite frequent here. There even used to be a few quarries, which are now closed. In very tiny brooklets the calcium carbonate, solluted in karstic water, is chemically precipitated, such that limestone is continually deposited to form a growing runnel, along which the water runs. There are ca. 25 such fragile objects known in heavely karstic territory of the Swabian Alb and the Franconian Jura.