Oderteich
| Oderteich | |||||||
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 runs over the dam (in front) |
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| Coordinates | 51 ° 46 '6 " N , 10 ° 32' 18" E | ||||||
| Data on the structure | |||||||
| Construction time: | 1715-1722 | ||||||
| Height of the barrier structure : | 17.3 m | ||||||
| Height above valley floor: | 19 m | ||||||
| Height above foundation level : | 22 m | ||||||
| Height of the structure crown: | 724.7 m above sea level NN | ||||||
| Building volume: | 36,500–42,000 m³ | ||||||
| Crown length: | 153 m | ||||||
| Crown width: | 16.1 m | ||||||
| Base width: | 34.6 m | ||||||
| Slope slope on the air side : | 1: 0.625 | ||||||
| Slope slope on the water side : | 1: 0.625 | ||||||
| Data on the reservoir | |||||||
| Altitude (at congestion destination ) | 723.35 m above sea level NN | ||||||
| Water surface | 30 ha | ||||||
| Storage space | 1.668 million m³ | ||||||
| Total storage space : | 1.83 million m³ | ||||||
| Catchment area | 12.2 km² | ||||||
| Design flood : | 31 m³ / s | ||||||
The Oderteich is a historic dam in the Harz Mountains . It is located near the Braunlager district of St. Andreasberg in the non- parish Harz region of the Lower Saxony district of Goslar and damms the water of the Oder .
The reservoir of the Oderteich was built between 1715 and 1722 by miners from Sankt Andreasberg and is operated by the Harz waterworks . Since July 2010 it has been a UNESCO World Heritage Site together with the other structures of the Upper Harz Water Regiment under the name Bergwerk Rammelsberg, Old Town of Goslar and Upper Harz Water Management .
The Oderteich was the largest dam in Germany until the end of the 19th century .
Geographical location
The Oderteich is located in the Upper Harz Mountains within the Harz National Park in the Braunlage - Sankt Andreasberg - Altenau triangle . Its dam is located 6.8 km northwest of the core town of Braunlage and 6 km north-northeast of the Braunlager district of Sankt Andreasberg. The reservoir lies between the Achtermannshöhe (approx. 920 m ) in the east-southeast, the Sonnenberg ( 853.4 m ) in the south-south-west and the Bruchberg (approx. 927 m ) in the west-north-west.
The Oder pond is fed by the Oder flowing in from the east and the Rotenbeek not far from it coming from the north-north- west ; About 350 meters above the confluence, the Rotenbeek takes on the small Bach Sonnenkappe from the west-north-west . The reservoir is elongated from the Rotenbeek in the north to the dam in the south. There are no villages by the pond; but in its catchment area lies the small Braunlager district of Oderbrück, 1.2 km east of the reservoir .
The federal highway 242 leads over the dam and joins the federal highway 4 about 800 m to the southeast . The larger Oder dam, completed in 1934, lies about 12 km to the south or below .
purpose
The Oderteich was built in order to reliably supply the water wheels of the Sankt Andreasberg mines with impact water via the Rehberger Graben, even in dry periods . Its capacity was sufficient to cover a dry period of around three months. It is the largest of all Upper Harz ponds .
Today the water of the Oderteich still drives several hydropower plants in Sankt Andreasberg, in the Samson pit and in the Sperrluttertal.
history
In 1703 the new Rehberger Graben was completed, which led Oderwasser to Sankt Andreasberg. This significantly improved the water supply to the mines there, but the Oder was unable to supply enough water after a long period of drought. This triggered considerations to further improve the power water supply by installing a water reservoir.
Ten to 15 kilometers further west, in the Clausthal-Zellerfeld and Hahnenklee area , 50 to 60 small dam structures were in operation at this time. The architectural style there could not be copied, however, as the turf used to seal the structure was not available in the area around the Oder pond.
In the meantime, they were in the process of "walling up" the Rehberger Graben , which was only created with wood fluff, that is, replacing the fled with a much more durable artificial trench made of earth building materials and dry masonry . It was found that thoroughly pounded granite gravel forms an effective seal.
The Vice Bergmeister Caspar Dannenberg wrote in 1712 two letters to the Mining Authority of Clausthal and proposed to build the dam or pond in granite masonry with a Granite crumb seal. This proposal has been implemented. Dannenberger , the spiritual father of the Oderteich dam, did not live to see the implementation; he died on April 23, 1713.
In August 1714 the planning of the project was finished. The surveyor Bernhard Ripking had created the first construction drawing, based on which Andreas Leopold Hartzig (1685–1761) wrote a cost estimate. Already on September 14th, King Georg Ludwig approved the construction of the Oderteich dam by a very gracious special order and provided the budgeted funds of "3048 Thalern 27 gl".
Construction began in the spring of 1715. First, a foundation trench was dug to which the dam seal was connected. The granite stones and granite sand required for the water and air side masonry were extracted from small quarries in the future storage space . This made it possible to enlarge the future basin contents at the same time.
The work dragged on until 1722. Since floods could neither be dammed nor drained via the - relatively small-sized - bottom outlet during the construction period, a flood relief system (outflow) had to be kept available that grew with the dam.
Shortly after the start of construction, it was first discussed whether the dam should be higher than originally planned. Ultimately, in 1717, after a lengthy discussion, approval was given to fill the dam to a total of nine pools (almost 18 meters) instead of the seven planned . This increased the embankment volume by 55% and the storage volume doubled to 1.67 million cubic meters.
Due to the increase and other influences, the construction costs increased considerably during the execution period: In the end, the Oderteichdamm cost around 11,700 Reichstaler , almost four times the originally estimated and approved amount. The king did not object to multiple requests for and approval of the supplements. The three responsible mountain masters and digging climbers were awarded cash prizes between 12 and 100 thalers in 1724.
Mining in Sankt Andreasberg came to a standstill in 1913. From then on, the systems of the Upper Harz Water Shelf were used to generate electricity: the water from the Oder pond continues to flow to Sankt Andreasberg and is used there in several power plants, especially in the Samson mine. This guarantees the economical operation of Oderteich and Rehberger Graben to this day.
At the end of the 1920s, the Harz waterworks planned a significant increase in the Oderteich dam. The dam and the geology of the area were thoroughly examined. The granite gravel seal was also exposed through scraping and it was found that it could hardly be worked with a pickaxe due to its high strength . These plans were not pursued any further for unknown reasons.
construction
The dam of the Oder pond differs considerably from the other dam structures of the Upper Harz water shelf. The dam structure is significantly higher and the storage volume is almost three times the cubature of the largest ponds around Clausthal-Zellerfeld and Hahnenklee. Other building materials were also used.
Dam
The dam was built between 1715 and 1722. It is 17.3 meters above the river bed and 22 m above the foundation level; Measured from the dam foot on the air side, the height is 19 meters. The crown is 724.7 m above sea level. NN height. According to various sources, the structure has a volume of 36,500 to 42,000 m³. At the crown it is 153 m long and 16.1 m wide; the foot has a base width of 34.6 m.
In the middle of the dam, up to 11.5 meters thick, is the dam seal made of pounded granite gravel . Normal embankment material was introduced to the left and right of this. The air- and water-side embankments consist of a Cyclops masonry made of large granite stones and an air- and water-side slope inclination of 1: 0.625.
The dam proves to be a very durable structure and, like the entire dam, is still practically in its original state. In principle, it is not entirely clear whether the Oderteich dam structure is a dam or a dam wall - a combination of both.
Bottom outlet (harrow)
The intention to use particularly resistant material for the Oderteich is best shown by the harrow system . At the lowest point in the valley, a shaft with a cross-section of about 1.10 × 1.20 meters was built into the dam. This shaft is lined with large hewn granite stones and extends to the natural valley floor. From the bottom of the shaft, an inlet channel 0.75 meters wide and 0.90 meters high leads into the storage space. This means that the pond's storage space always communicates with the water level in the shaft. Of the shaft bottom two lead Holzgerenne oak with square cross-sections of about 25 x 25 centimeters to airside Dammfuß. They have an inlet from above at the bottom of the shaft, which is closed by a harrow pin, similar to a bathtub plug. This pin can be pulled or lowered from the harrow house above the shaft using a rod . The oak run is installed in such a way that it is always under water even when the bottom outlet is closed and thus hardly rots. The entire bottom outlet construction is called a harrow .
In 2016 it was found that both wood runs are defective. They had larger defects; the water had created cavities through the surrounding sealing material, so that large quantities of it found its way out of the harrow shaft past the closure element into the run. A plastic pipe was therefore inserted into both runs, and the remaining space and the cavities were grouted with a powdered clay-cement mixture. The original Holzgerenne thus remained in its place; The harrow as a closure organ also continues to fulfill its original function.
The big outflow
Every dam needs a flood relief system so that even exceptionally large floods do not lead to overflowing the dam crest. At the Oderteich it is at the eastern end of the dam.
In the storage space in front of the outflow , there are some menhir-like granite steles about 2.50 meters high . They serve to keep ice floes away from the overflow, as these could block the drainage cross-section . The contactor system of old Ausflut in 1895 by the Royal Central forge Clausthal made. It makes it possible to increase the traffic jam destination by another meter.
Originally, the outflow led almost 100 meters further south, before the water could tumble down into the valley. This route is still visible to the trained eye in the area. When, towards the end of the construction work in 1722, stones were still missing to complete the dam, the steeply sloping and approximately 80-meter-long large outflow from the rock was blasted about 60 meters below the protective system at a right angle to this outflow, which would probably be a cheaper hydraulic one Hoped for efficiency . The shooting range carved into the rock is very impressive, especially during operation.
The outflow was initially insufficiently dimensioned. In December 1760, the dam was overflowed during an extraordinary flood. Due to the stable dam construction, only minor damage occurred. The reaction was to raise the dam by one meter, which probably only compensated for the dam that had been set up until then .
In 1886/87 it was concluded that the efficiency of the outflow had to be increased further. For this purpose, a further outflow was built a few meters east of the existing outflow, at the inlet twelve meters wide, the overflow threshold of which is about one meter above the threshold of the old main outflow. It crosses under the B 242 parallel to the main flood and merges with it shortly before the overflow level and the subsequent weft. This enabled the efficiency of the flood relief system to be increased by around 50%.
Storage space
The Oderteich has an area of 30 ha . Its storage space (storage space) is 1.668 million m³ and its total storage space is 1.83 million m³. The target is at 723.35 m above sea level. NN height. Its catchment area is 12.2 km². The design flood is 31 m³ / s. The degree of expansion of the Oder pond is very low: its storage space can only store 14% of the annual flow. This explains the high fluctuations in the water level. With largely empty storage space, the pond can fill up to the point of overflow within a few hours and usually overflows several times a year.
There are no fish in the Oderteich. Presumably the relatively acidic environment of the water does not offer them a habitat. A large part of the water comes from raised bog areas and has a high proportion of humic acid . This reduces the surface tension and causes the brown color of the water as well as noticeable foam crowns in the inflow and outflow.
Power generation
To generate electricity, the Oderteich always releases 200 to 300 liters of water per second into the Rehberger Graben. As soon as the inflow is lower than the output, the water level in the pond drops. If the drought persists for several months, the pond can also fall completely empty. This happens roughly every five to ten years, the last time it happened in 1999, 2003 and 2018.
Largest dam
The Oderteich is often referred to as the oldest dam in Germany. However, this is not correct, as there were already a large number of dams in the Ore Mountains and Upper Harz in the Middle Ages , which according to the dam definition are to be classified as dams. However, from its completion until the end of the 19th century, it was the largest dam in Germany for a period of 170 years. With regard to the water level, it was exceeded in 1891 by the Eschbachtalsperre in Bergisches Land , which had a 23 m high dam. In terms of storage volume, the Oderteich was only replaced in 1899 by the Lingesetalsperre with a storage volume of 2.6 million cubic meters.
Tourist development
Swimming is permitted in the southern third of the Oder pond, i.e. near the dam. The northern area is demarcated by a swimmer chain in summer and should only be left to nature. There is an approximately 4.5 kilometer long circular hiking trail around the pond, which in parts leads as a boardwalk through high moor-like areas. The Rotenbeek (Sonnenkappe) brook, which flows into the Oderteich in the north, is included as No. 217 in the system of stamping points of the Harz hiking pin; the stamping point is on its west bank - near the mouth of the stream in the reservoir.
Use of ice sports in winter is not recommended, as the rapidly changing water level makes it considerably more difficult to form a stable ice cover, especially in the bank area.
By the operators of the pond or the resin waterworks , the mid-1990s was an information "water trail" created. This leads over the dam crest to the two outflows, points to the two additional collecting trenches and goes over the overflow level along the large outflow and its weft channel down to the dam foot on the air side. From there you have a view of the air-side masonry of the dam and the outlet of the bottom outlet as well as the beginning of the Rehberger Trench. Information boards along this path explain the various structures.
Others
The view of the embankment is characterized by the B 242 running on the crown, which is not considered to be a monument. Efforts on the part of the national park and the monument protection authorities to make the road more pleasant have regularly failed due to the safety understanding of the authorities responsible for the road. For these reasons, it has not been possible to date to replace the guardrails with other constructions.
When the water level is lowered, some places where the material was removed for the construction are clearly visible. The east bank is littered with large granite stones in the northern, unaffected area. In contrast, near the embankment there are almost beach-like conditions: In this area, the granite stones were all removed to use them in the masonry or as embankment fill material. Similar conditions can also be seen on the west bank, when the pond is very empty you can still see the remains of a quarry.
Until the 1960s, most recently used as a restaurant was at the western end of the dam pond keeper's house . After the constant presence of the pond keeper was no longer required, it was demolished. The foundation walls of the building can still be seen faintly in the corner on the air side of the main road. A ski hut built by MTV Goslar in the late 1940s is also used as self-catering group accommodation.
When the Oder pond is completely emptied, the remains of an emergency dam can be seen in the storage space about 200 meters above the main dam . This was created in 1898 in order to be able to reduce the water flow into the bottom outlet during a harrow repair. The emergency dam is said to have broken when the repair was completed.
About ten kilometers downstream south of the pond Or was that in 1934 Odertalsperre completed, which is sometimes confused with the Teich. Apart from the similarity of names and the fact that both dam structures impound the same river, there are no parallels.
Trivia
In the winter of 1928/29 the aviation pioneer Walter Spengler landed on the frozen Oderteich.
See also
- Dams in the Harz Mountains
- List of dams in Germany
- List of lakes in Lower Saxony
- Rammelsberg mine, old town of Goslar and Upper Harz water management
literature
- Peter Franke, Wolfgang Frey: Dams in the Federal Republic of Germany . Systemdruck, Berlin 1987, ISBN 3-926520-00-0 .
- Hugo Haase : Engineering structures of old water management in the Upper Harz. Sloping ditches, ponds, tunnels in the landscape, economy and history . Edited and expanded by Wolfgang Lampe . 5th edition. Pieper, Clausthal-Zellerfeld 1985, ISBN 3-923605-42-0 .
- Markus Liebermann, Wilfried Ließmann , Andreas Rutsch: 300 years of the Neuer Rehberger Graben. = Jubilee celebration 300 years Rehberger Graben (= contributions to the mining history of Sankt Andreasberg. Volume 3) . Self-published, Sankt Andreasberg 2003.
- Martin Schmidt : The Oberharzer Wasserregal cultural monument ( Memento from July 19, 2011 in the Internet Archive ), accessed on May 3, 2016, at archive.org, as of July 2010, from harzwasserwerke.de (PDF; 1.74 MB)
- 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 , p. 380 .
Web links
- UNESCO World Heritage in the Harz Mountains
- Cross-section through the embankment of the Oderteich (graphic), in water management , on lehrbergwerk.de
- The Oderteich , on harzlife.de
- UNESCO World Heritage Upper Harz Water Management - The Upper Harz Water Shelf (leaflet with an overview map of all active systems), on harzwasserwerke.de (PDF; 525 kB)
References and comments
- ↑ a b c d e Detail of the cross section of the Oderteich dam from the information panel Der Oderteich (photos), on myheimat.de
- ↑ a b c Deutsches Talsperrenkomitee eV (Ed.): Talsperren in Deutschland , Springer Vieweg-Verlag, 2013, p. 166
- ↑ a b c d e f g h i j k l From the water rights application of the Sankt Andreasberg Forestry Office of January 15, 1965, unpublished
- ↑ "Oberharzer Wasserregal" declared a World Heritage Site. tagesschau.de , August 1, 2010, archived from the original on August 4, 2010 ; Retrieved October 2, 2012 .
- ↑ a b Martin Schmidt: The cultural monument of the Upper Harz water shelf , 2005
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 147
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 148
- ^ Letters from Caspar Dannenberger to the Clausthal Mining Authority of December 24, 1712 and February 27, 1713, Clausthal Lower Saxony Mountain Archive
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, pp. 150-152
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, pp. 155 and 181
- ↑ Note: Reichstaler and Mariengroschen , see also German currency history before 1871 # The money and coin system as well as groschen
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 156
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 170
- ↑ a b Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 177
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, pp. 174-176
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, pp. 179-180
- ^ Hugo Haase: Engineering structures of old water management in the Upper Harz . 5th edition. Pieper, Clausthal-Zellerfeld 1985, ISBN 3-923605-42-0 , p. 128-131 .
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 147 ff.
- ↑ Note: What is meant is soil that can be easily extracted and built in the vicinity, regardless of its other properties
- ↑ Note: This statement is justified in particular by the fact that the barrier structure was not statically dimensioned.
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, pp. 162-165
- ↑ Justus Teicke, Katharina Malek : The Oderteich - A 300 year old dam and its repair in: Our Harz, history and stories, culture and nature from the entire Harz, Clausthal-Zellerfeld, issue 1/2017
- ↑ Bretschneider, Lecher, Schmidt: Taschenbuch der Wasserwirtschaft . Paul Parey Verlag, Hamburg and Berlin 1982, p. 627 .
- ↑ Justus Teicke: Dams on the way to becoming a world cultural heritage: The Upper Harz water shelf . In: Proceedings of the 14th German Dam Symposium, reports from the chair and the research institute for hydraulic engineering and water management . Technical University of Munich, Munich September 2007 ( [1] (PDF; 1.55 MB)). online ( Memento from May 18, 2016 in the Internet Archive )
- ↑ Sign on the protective system, which disappeared in the 1980s.
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, pp. 187-188
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 189
- ↑ a b Oderteich almost empty , press release from August 7, 2003, on oderteich.harzwasserwerke.de (PDF; 43.6 KB)
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 182
- ↑ Oderteich circular hiking trail , at nationalpark-harz.de
- ↑ Harzer Wanderadel: Stamp number 217 / Sonnenkappe Oderteich , on harzer-wandernadel.de
- ↑ Warning signs of the operator Harzwasserwerke on the banks
- ↑ Martin Schmidt: WasserWanderWege, a guide through the Upper Harz water shelf - world cultural heritage . Ed .: Harzwasserwerke GmbH. 4th edition. Papierflieger Verlag, Clausthal-Zellerfeld 2012, ISBN 978-3-86948-200-2 .
- ↑ Martin Schmidt: The water management of the Upper Harz mining industry . 2002, p. 191
- ↑ Böblingen Airport Stories - Walter Spengler… one of the four pilots who died in the crash of the acrobat Fritz Schindler on flughafenbb.wordpress.com
