Lower Schalke Pond
| Lower Schalke Pond | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 |
|||||||||
|
|||||||||
|
|||||||||
| Coordinates | 51 ° 50 '12 " N , 10 ° 23' 39" E | ||||||||
| Data on the structure | |||||||||
| Lock type: | dam | ||||||||
| Construction time: | 1730 | ||||||||
| Height above valley floor: | 11.28 m | ||||||||
| Height of the structure crown: | 509.39 m | ||||||||
| Crown length: | 97.2 m | ||||||||
| Crown width: | 14 m | ||||||||
| Base width: | 50 m | ||||||||
| Data on the reservoir | |||||||||
| Altitude (at congestion destination ) | 508.81 m | ||||||||
| Water surface | 2.81 ha | ||||||||
| Reservoir length | 290 m | ||||||||
| Reservoir width | 120 m | ||||||||
| Total storage space : | 151 000 m³ | ||||||||
| Catchment area | 1.87 km² | ||||||||
The Untere Schalker Teich , also simply called Schalker Teich , is a small dam that was created in connection with the Upper Harz water shelf near Schulenberg in the Upper Harz . With a dam height of 11.28 meters, it accumulates 151,000 cubic meters of water. The dam is one of the Upper Harz ponds and is part of the Rammelsberg World Heritage Site , the old town of Goslar and the Upper Harz Water Management .
history
The pond was created in the years 1729 to 1733 to supply water to the pits and stamping works below , to which the water was partially fed with ditches.
Today several hiking trails run along the Lower Schalke Pond, in particular to Schalke , Festenburg and Mittelschulenberg .
Naming
The Schalke pond takes its name from the Schalke brook of the same name , which is dammed here. The stream is named after the mountain of the same name, Schalke , from which it rises. The corresponding valley is also called Schalketal .
The dam burst on December 26, 1733
The dam broke on Boxing Day 1733. The resulting tidal wave fell victim to seven people in the village of Schulenberg below, as well as twelve cows and a horse. There was also considerable property damage. Since the mining authority immediately initiated an investigation, which is well documented in the logs, the course of this dam breach and its causes can still be traced well today:
The Lower Schalke Pond was completely rebuilt between 1729 and 1733 as a new type of pond, i.e. with a core seal in the middle of the dam. In 1733 it had reached its final height. At the time of the accident, it was still in a trial jam.
Already 14 days before the break, the responsible ditch climber discovered cracks in the dam crest, namely cracks along the dam between the sod seal and the embankment embankment on the water side. In the week before Christmas, local subsidence of several centimeters was found in the embankment embankment on the water side, as well as new and larger cracks in the longitudinal direction of the embankment between the seal and embankment embankment on the water side. These cracks and settlements were repeatedly filled and evened out by the staff; last on the day of the accident, 20 men were busy on site to fill in the constantly emerging settlements and cracks. Towards evening the dam broke with a loud crack in the eyes and ears of diggers and workers.
The cause of the accident can now be easily understood: Up until 1714, the Upper Harz dams were built with a seal on the embankment on the water side (old construction). The Lower Schalke Pond was one of the first ponds of the "new" type and now had its seal in the middle of the dam. This type of construction had a decisive disadvantage compared to the "old" type: Since only the area behind the seal is available in the dam body as an abutment against the water pressure , the support body has shrunk considerably.
In a pond dam with a dam height of around 10 m, the accumulated water presses with a force of 50 tons on every running meter of dam. The pressure acts on the place where the seal sits and can push the dam away if it does not have enough mass behind the seal or if the embankment is not sufficiently interlocked with the subsurface.
With the old design, almost the entire dam body was available except for the seal and a possible shaft protection lining as an abutment against the water pressure, with the new design it is only about half of the total embankment. With that, the water pressure had literally pushed the dam away.
The dam of the Lower Schalke Pond was re-filled in 1734 with a core seal, but much wider.
Others
There was also a middle and an upper Schalke pond . Both dams were shut down in the 19th century. The reasons for the closure were, on the one hand, technical problems (leaks) and, on the other hand, the decreasing water demand of the mines to be supplied. The impressive remains of the dams in these two ponds can still be seen a few hundred meters above in the valley. They also form soil monuments and thus belong to the passive systems of the Upper Harz water shelf.
On July 26, 2017, the residents of Oberschulenberg were temporarily evacuated because the dam of the Upper Schalke Pond, which was actually out of service, broke after long periods of heavy rainfall and a strong tidal wave flowed into the Schalke Pond. One was not sure whether the Schalke pond could withstand this tidal wave. In fact, the incident turned out to be safe and the dam structure survived the extreme overload without damage. Damage only had to be repaired in the flood relief system.
Picture gallery
Lower Schalke Pond seen from the dam, September 2014
Water surface of the Schalke pond
Hubertusquelle Middle Schalke Pond
See also
- Dams in the Harz Mountains
- Upper Harz ponds
- List of dams in Germany
- List of dam accidents
- List of lakes in Lower Saxony
literature
- Martin Schmidt : The water management of the Upper Harz mining (= publication series of the Frontinus Society . Issue 13). 3rd supplemented edition. Harzwasserwerke, Hildesheim 2002, ISBN 3-00-009609-4 .
Web links
Individual evidence
- ↑ Axel Wellner: The dam break of the Schalke pond 1733 . In: Der Schläger, bulletin of the Upper Harz History and Museum Association . Upper Harz History and Museum Association, Clausthal-Zellerfeld June 1999.
- ↑ Lower Saxony Mountain Archive, Clausthal-Zellerfeld, File No. 1165/24
- ↑ Martin Schmidt: Particular cases of damage to the Upper Harz pond dams. In: Leichtweiß Institute for Hydraulic Engineering at the Technical University of Braunschweig. Messages. Issue 103, 1989, ISSN 0343-1223 , pp. 383-421 (also special print).
- ↑ Justus Teicke: The dam break of the Schalke pond from a technical point of view . In: Der Schläger, bulletin of the Upper Harz History and Museum Association . Upper Harz History and Museum Association, Clausthal-Zellerfeld September 1999.
- ^ Andreas Rietschel: Oberschulenberg is being evacuated. In: Goslarsche Zeitung Online. July 26, 2017. Retrieved August 2, 2017 .
- ↑ Justus Teicke, Katharina Malek , Der Bruch des Oberen Schalker Teichdammes in July 2017 in: Our Harz, history and stories, culture and nature from the entire Harz, Oberharzer Druckerei and Verlag Fischer & Thielbar GmbH, Clausthal-Zellerfeld, issue 6/2020 , Page 103 ff