Kellwassertal
The Kellwassertal is the side valley of the Upper Harz Oker Valley, most strongly formed by glaciers from the Ice Age . It stretches for about eight kilometers from Altenauer district Torfhaus northwestward down to Okertalsperre , in their pre-dam the lowest Talstück is included. The valley is named after the Kellwasser stream and is 60 to 150 meters deep into the northern roof of the Hochharz and the somewhat lower Upper Harz rump area . The valley is almost completely occupied by forest areas in which the spruce dominates.
Relief forms and the steep wall cirque
The lower section of the valley is carved into the wavy Upper Harz plateau, which is slightly hollowed towards the Okertalsperre, with not very high, moderately steep slopes. Up the valley, with the rise of the mountains to Brockenfeld and Bruchberg , the valley floor gradually widens with increasingly high, very steep slopes and then apparently ends in a basin-like valley head , which is enclosed in a semicircle by the steep wall, which towers almost vertically up to 80 meters . He's an Ice Age glacial cirque , which is exceptionally clear pronounced for the Northern Mountains.
On both sides, streams cascade down into the valley basin: from the east over boulders the former upper course of the Kellwasser, which is diverted in the valley floor through a slope channel to the dam ditch , from the west in an almost gorge- like gorge the secondary brook Nabe, which is also mainly derived to the dam ditch above . Both streams have been pushed to the valley flanks by the former glacier edges and have been fixed there by lateral moraines after they have melted . In the past, the hub seems to have only reached the Kellwasser valley parallel to the Kellwassertal via the Großer Spritzental, before one day it was able to break out to the Kellwassertal valley, which is immediately next to it and which runs much deeper, and subsequently cut the gorge with small waterfalls.
This large basin represents a hybrid between a confluence stage and a glacial cirque. The confluence stage was created where part of the ice, bundled into a glacier tongue, flowed north from the northern edge of the plateau glacier between Bruchberg and Brocken . The glacier cirque, which deepens this basin towards the southwest, was mainly formed by solidified snow that had previously been blown from the Bruchberg and could collect here in its slipstream.
geology
The Kellwassertal is largely sunk into the Grauwacken of the Lower Carboniferous , which are interspersed with layers of clay slate . But older rocks of the Upper Devonian are also cut, of which the dark banks of the Kellwasserkalke are particularly noteworthy, which testify to one of the largest mass extinctions in the history of the earth, which is known as the Kellwasser event . The type locality is protected as a geotope . The upper, steeper valley section is cut into the quartzite sandstone of the Acker-Bruchberg-Zug . The source area is in the area of the Brocken granite . The eastern part of the steep wall is made up of porphyry granites , in its almost vertical middle part of silica slates , which are solidified to horn rock in the contact area with the former embers of today's granite , and in the north-western part of comb quartzite. In Kellwassertal extending partly Bock Wieser lode , a to the Oberharzer veins counting gait disturbance .
In 1850 the geologist and botanist Friedrich Adolph Roemer demonstrated the mass extinction of flora and fauna species at the Frasnium - Famennium border about 372.2 million years ago using a geological outcrop, the Kellwasserkalk . This biological turning point is still called the Kellwasser event today .
Sloping ditches and waterfalls
Through the upper Kellwassertal, only a significantly reduced amount of water reaches the Oker when the water flow is low, because above and below the steep wall the water is intercepted in artificial ditches and directed westwards over the dam ditch towards Clausthal-Zellerfeld . There it is no longer used for mining purposes today, but is returned to the Oker. The trenches are part of the technically complex, historic Upper Harz water shelf . From the river basin of the Radau the Abbegraben Wasser leads to the former upper reaches of the Kellwasser, just like the Flörichshaier Graben from the river basin of the Oder . Therefore, the cellar water cascades east of the boiler are usually impressive. Below, the water is drained from the valley into a tunnel in the Upper Harz watercourses and passed over the hub gorge in a small aqueduct . The upper hub, in turn, is supplied with water from the south side of the Bruchberg via the Clausthal flood ditch, which then flows like a torrent in the creek bed of the hub towards the beginning (the so-called cradle ) of the dam ditch. The well-known Nabental waterfall is a hydraulic engineering term for this section in which the water “falls” freely. In the subsequent pathless gorge, which has almost fallen dry due to the water drainage, the hub forms real waterfalls .
Tourist development and nature protection
The Kellwassertal is a destination for hiking, biking or skiing. A partially asphalted path through the valley begins at the level of the Okerstausees and ends at federal road 4 between Braunlage and Bad Harzburg . The Kellwasser nature trail runs along it . The most interesting part, the Steile-Wand-Kar, is mostly seen from the parking lot at Hedwigsblick on Steile-Wand-Straße, but can also be hiked along Magdeburger Weg at the foot of the wall line. It turns into the Dammgraben water hiking trail .
The waterfalls and the Karboden are inaccessible to the general public due to the trails in the Harz National Park .
literature
- Ernst Andreas Friedrich : Lower Saxony. Treasury of nature , Hanover, 1987 (Landbuch-Verlag GmbH) ISBN 3-7842-0369-8
Coordinates: 51 ° 48 ′ 47 " N , 10 ° 29 ′ 41" E