Nixseebecken

Location:	A7 exit Seesen(Harz), B243 48 km through Osterode, Herzberg and Bad Sachsa to Nüxei. At the turnoff to Tettenborn. (29,Ld39)
Klassifikation:	Polje. border Staßfurt Dolomit - Werra Anhydrit
Dimension:	Springwiese: AR=2.5 ha. Tal: L=400 m, B=50 m. S-Becken: 8Ha. Fitzmühlenspring: Y=20 l/s.
Photography:	allowed
Accessibility:	Yes
Bibliography:	Das Nixseebecken, ein Polje im Gipskarst des südwestlichen Harzvorlandes, in: Der Südharz - seine Geologie, seine Höhlen und Karsterscheinungen, Jh. Karst- u. Höhlenkunde, Heft 9, München, 1969
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.

Description:

The Nixseebecken is a depression, consisting of a Springwiese (a meadow with springs) in the North, a ~400 m long valley, and the artificially dammed Nixsee in the South. About 500 m north of the spring meadow the Zehntgärtenbach disappears in the Großen Trogsteinhöhle.

The spring meadow is irregular shaped, bordered by 30° to 60° steep slopes. In the northeast an outcrop of gpsum is karstified, the cliff face of this outcrop is called Kalkberg. A karst spring emerges here, called the Fitzmühlenspring, and several more are located in the meadow. The water in all those springd is the reappearing water of the Zehntgärtenbach plus water which rains on the surrounding hils.

The different watercourses unite and flow through the 400 m long and 50 m wide valley to the south into the Nixsee. This lake is located inside an about 400 m x 200 m large depression. At the east end of this basin is a ponor (swallow hole). Normally the water would disappear at this point but the Nixsee was dammed up by a dam in front of the ponor.

The entire valley or depression of the Nixseebeckens is located at the same level as several nearby sinkholes, the largest of which is called Weissensee.. Some of them are filled with water. Very interesting is the fact that the water level of Lake Weissensee is 10 m higher than the Ponor, although it is only 100 m away. This indicates that his water circulates in an independent underground water course.

There are two possible explanations, how the Nixsee Basin was created:

Either it is a partially collapsed cave system, its still existing parts are the various spring caves and the ponor.
Or over time several sinkholes, like the Weissensee, grew together to form a big depresion.

The Nixsee basin is a part of the Karstwanderweg, a famous trail along the karst features of the southern rim of the Harz.