Blautopf

Geschichte

The Blautopf is a spring that serves as the source of the river Blau in the karst landscape on the Swabian Jura's southern edge, in Southern Germany.DescriptionThe Blautopf is located in the city of Blaubeuren, approximately 16km west of Ulm. It forms the drain for the Blau cave system, where the Blau after 14.5km flows into the river Danube in the city of Ulm. Because of its high water pressure, the spring has developed a funnel-like shape, which at its deepest point has a depth of 21 metres (69 ft). The water's peculiarly blue color, varying in intensity due to weather and flow, is the result of physical properties of the nanoscale limestone densely distributed in the water. The particles are so small that the so-called Rayleigh scattering of light takes place, preferentially scattering the blue color in the visible light. Similar effect is observed at the Blue Lagoon in Reykjavik, Iceland, where the blue color originates from nanoscale silica particles.Near the Blautopf is a hammermill fed by the water of the spring. A film, which documents the exploration of the cave, is shown at the same location.GeologyThe Blautopf is a spring in a Karst environment. One characteristic of a Karst environment is that water, which drains quickly through the limestone in one area, surfaces in another. Karst environments only have subterranean drainage, and there are no bodies of water above ground. Therefore, the size of the Blautopf depends greatly on the level of rainfall, though it never entirely dries out. The Blautopf is the second largest spring in Germany, after the Aachtopf.