Aachquelle

Aach Spring

Useful Information

The spring itself. Below the bridge the cave starts.

Location:	A81 exit Engen, B31 to Aach, in the village. (47.846681, 8.858106)
Open:	no restrictions. [2021]
Fee:	free. [2021]
Classification:	Karst Spring Upper Jurassic (Malm) limestones.
Light:	n/a
Dimension:	see table below
Guided tours:	self guided
Photography:	allowed
Accessibility:	yes
Bibliography:
Address:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1705	a loss of water between Immendingen and Möhringen is first mentioned.
1719	first hypothesis about an connection between Aach spring and Danube sink.
1886	ein Helmtaucher erkundet den Eingangsbereich des Aachtopfes.
1962	Jochen Hasenmayer dives 300 m into the Aach spring cave.
1963	mortal accident of an diver in the Aach spring cave.
1969	Jochen Hasenmayer dives 400 m into the Aach spring cave.
1979	mortal accident of an diver in the Aach spring cave.
1980	Harald Schetter revives exploration of the cave.

Description

the other direction, view down the Aach river.

The Aachtopf (Aach spring) is the resurgence of the Karst Donauversickerung. This was proven by a dyeing experiment. The water is swallowed in Malm beta reappears in the Aach spring in Malm zeta. This means, the water flows from the older and lower strata into the younger and higher strata. The explanation is easy: the layers fall steeper than the karst water table.

The time, the water needs from the Danube to the Aach spring, is rather short. During this time, the water changes its temperature only a little bit, the temperature of the spring water depends very much on the temperature of the Danube water. And of course, the water looses very little of its contents, unlike water in detritus, which is cleared by microorganisms. All this facts proof the existence of a huge cave system betweendanube and Aach spring. Its not really sure, they are big enough to allow humans to enter them, but it is very likely.

The Aach spring forms a small lake, similar to the one at the Spring Blautopf, but unlike the Blautopf, this spring is not deep with a cave at the bottom. The lake and the cave are rather shallow. The first one to explore the cave was Jochen Hasenmayer, the most famous German cave diver. He explored 1962 300 m of the cave, and in a second try 1969 he diver 100 m further. He found that the cave runs straight to the North. At 130 m he discovered a big chamber, which he named Strömungsbahnhof (train station of the stream). In 1971 he discovered Speleothem rimstone pools and other dripstones at 17 m below water level, which proofs that this cave once was a Speleology river cave, only partially filled with water.

In the neighbourhood of the Aachtopf are 11 more little springs, most of them inside the Aach river, some at the shores of the river.

path of the water from the Danube sink
length	11.7 km
downward slope	1.5 %
velocity	195 m/h
production:
average	8,590 l/s
max	24,100 l/s
min	1,310 l/s
cave:
length	400 m
depth (below water level of the spring)	18 m
altitude	481 m asl
catchment area	240 km²
amount of limestone in the water	3,000 m³