Möhne reservoir

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Möhne reservoir
Moehnetalsperre2.jpg
Location: District of Soest , North Rhine-Westphalia ( Germany )
Tributaries: Möhne , Heve
Drain: Möhne
Larger places on the shore: Baskets , Delecke , Günne
Major cities nearby: Soest , Arnsberg
Möhnetalsperre (North Rhine-Westphalia)
Möhne reservoir
Coordinates 51 ° 29 '23 "  N , 8 ° 3' 33"  E Coordinates: 51 ° 29 '23 "  N , 8 ° 3' 33"  E
Data on the structure
Construction time: 1908-1912
Height above valley floor: 32.44 m
Height above foundation level : 40.3 m
Height of the structure crown: 214.86 m
Building volume: 267,000 m³
Crown length: 650 m
Crown width: 6.25 m
Base width: 34.2 m
Power plant output: 7.04 MW
Data on the reservoir
Altitude (at congestion destination ) 213.74  m above sea level NHN
Water surface 10.37 km²dep1
Storage space 126.05 million m³
(main dam only) ;
134.5 million m³
(with 2 largest pre-dams and compensation basin)
Catchment area 436.29 km²
Design flood : HQ1000 = 246 m³ / s

The Möhnesee is a reservoir on the Möhne . It is located in the municipality of Möhnesee in the Soest district in North Rhine-Westphalia . At the destination of the reservoir , the main dam has 10.37 square kilometers of water surface and a storage space of 126.05 million cubic meters; with the two largest pre-dams and an equalization basin , there are 134.5 million cubic meters. The water is dammed up by a 40.3 meter high and 650 meter long dam wall.

Geographical location

The Möhnesee lies on the north-western edge of the Arnsberg Forest Nature Park . South along the the Westphalian bay on conducting Haarstrang he runs in an east-west direction through the eponymous municipality Möhnesee and dams, in addition to smaller streams that Möhne and Heve .

Geological subsoil

The contact area of ​​the dam is located in the upper area of ​​the loosening zone of the Upper Carboniferous Arnsberg layers, an alternating layer of intensely folded sandstones , greywacke and claystones . The rocks were intensely folded due to intensive tectonic stress during the Variscan mountain formation . The Möhnetal area is also characterized by the presence of large fault zones . To the north of the dam, the folded paleozoic layers are discordantly overlaid by deposits of the Münsterland chalk . The Upper Cretaceous sequence falls flat in northerly directions and begins with a glaconite-containing greensand of the Essen-Greensand Formation from the Cenomanium and is made up of Planer limestone of the Erwitte Formation of the Coniacian and Turonian and the marls of the Büren Formation and the Planer of the Oerlinghausen Formation of the turonium superimposed. The geological boundary between the Paleozoic and Cretaceous layers also forms the geographical and natural boundary between the Arnsberg Forest ( Sauerland ) and Haarstrang .

Uses

The Möhnetalsperre is used to increase the low water level , to protect against floods and to generate electricity from hydropower. The primary goal is to raise the low water level in the Ruhr , into which the water from the dam reaches the lower reaches of the Möhne and the confluence in the Arnsberg district of Neheim. The regulation of the water level in the Ruhr guarantees an even supply of raw and industrial water to the Ruhr area . The Ruhrverband is the owner and operator of the dam .

The Möhnesee, which, along with the Rurtalsperre and Biggesee, is one of the largest reservoirs in North Rhine-Westphalia, as well as the adjacent Arnsberg Forest, are important local recreation areas , especially for people from the Ruhr area . That is why there is an extensive range of water sports on offer as well as a large triathlon competition on Lake Möhnesee every year. Barbecuing on the lake, sailing, motor boating with an electric motor and diving to depths of 25 meters are possible here. The Möhnetal cycle path from Brilon to Neheim runs along the lake on both sides .

Main lock

Storage space

The storage or storage space of the main dam can hold 126.05 million m³ of water. With its four sections, the Möhnesee is over ten kilometers long and around 10.37 km² in size. When it is fully backed up, its deepest point is 36 meters at the Linkturm, which was named after the builder Ernst Link .

Dam wall

The barrier structure of the dam, which was built as a gravity dam, consists of quarry stone masonry, is built according to the Intze principle and has a crown length of 650 m.

In order to enable an overflow during floods, 105 openings are made in the top of the wall, below the roadway. Part of the energy of the water flowing down is already converted on the air side of the dam by the protruding quarry stone blocks. In order to protect the wall and because of the generation of energy, overflow through the openings of the flood relief is avoided as far as possible. The dam last overflowed in August 2007, due to extreme rainfall in the catchment area - for example in Warstein on August 9, 2007 in three hours 58.5 mm. The penultimate overflow event was in 1984.

Equalization basin and hydroelectric power station

Directly below the dam there is a compensation pool (compensation pond) that serves as a stilling pool . The storage space is 0.65 million m³ and the storage target is 183.6  m above sea level. NHN .

The hydropower plant has an expansion capacity of 7.04  MW ; its mean total annual energy production is 12.9 million kWh .

Pre-locking

The Möhnesee has three pre-locks (pre-basins); Looking down on Möhne these are:

Carrion foothills

The Möhne feeds the Möhne pre-basin directly to the east of the main dam, the storage capacity of which can hold 7 million m³ of water. The water is dammed up by the Stockumer Damm located south of Stockum , on the west side of which the main basin meets directly.

Wamel pre-basin

The Wamelvorbecken lies at the influence of the Wameler Bach in the main dam. A Lehmschüttdamm over which the county road  8 in section Völlinghausen - Wamel -Stockum leads, separating it from the main pool. The normal congestion target is 213.74  m , the summer congestion target is 212.5  m . The dam is 14 m high and about 580 m long. At the crown it is 12.65 m wide, at the foot a maximum of 75 m.

Heving basin

The old bridge in the heave basin, one of two sedimentation basins, which was emptied for repair work

The Heve fore basin lies at the influence of the Heve in the main dam. It is separated from the main basin by an embankment dam, over which the federal road 229 runs in the section Breitenbruch - Delecke . The normal congestion target is at 213.74  m , the summer congestion target at 213  m . The dam is 12 m high and about 320 m long. At the crown it is 12 m wide, at the foot a maximum of 41 m. The storage space is 800,000 m³.

nature and environment

Overflow of the dam in 2007

The Möhnesee is designated as a European bird sanctuary " Möhnesee " in the Natura 2000 protected area system of the EU .
The Hevesee and the Heve-Arm in the south of the Möhnesees as well as the inlet of the Möhne into the lake are designated as nature reserve Hevearm and Hevesee . The Hev pre-basin and adjacent areas have also been registered as an FFH area .

With four to six thousand water birds, the Möhnesee is an important resting place in North Rhine-Westphalia. The major catch birds, with percentages for the years 2001 to 2006 the number of pension at 31 per cent, the mallard with 24 percent, the coot with 22 percent of grebes with 9 percent who Pochard 5 percent and other species with 9 percent. An important reason for the greater number of diving ducks and coots resting is the presence of the migrating mussel in the lake. The migrating mussel forms mussel beds with several thousand animals per square meter on the stony bottom of the lake. At the influences of the Möhne and the smaller streams in the lake there are occurrences of kingfisher , gray wagtail and dipper . Their actual breeding sites are not directly on the lake, but on the tributaries. On the lakeshore breeding mallard, tufted duck, moorhen , coot, Mute Swan , Greylag Goose , Canada Goose , Egyptian Goose and grebes. The great crested grebe has its largest breeding population in Westphalia with around fifty breeding pairs on the lake. The gray heron has a breeding colony on the Westenberg in Wamel with 15 to 30 occupied eyries . The cormorant has so far only made unsuccessful breeding attempts, presumably because of human interference. The red-necked grebe has also brooded at the lake several times without success. In the little grebe, however, there have been individual successful breeds in the past. A special feature was the year-round occurrence of the eider , a sea ​​duck , from September 2001 to December 2006. In July 2006, the first proof of breeding for North Rhine-Westphalia was provided here: a female with three teenage cubs. When the water level rose sharply in December 2006, the eider ducks could no longer reach the migrating mussel beds and left the lake. Other sea ducks also appear more frequently in the winter time.

13 fish species were found in the lake during trial fishing by the Ruhr Association . The largest stocks come from river perch with 53 percent, ruff with 20.3 percent and roach with 13.9 percent. In addition, there are great whitefish , eel , pike , pikeperch , vendace , lake trout , bream , carp , tench and chub . Lake trout and eel only occur because of an artificial population and do not reproduce naturally. There is also the muskrat .

history

Design of the Möhne Reservoir, architect Franz Brantzky, 1907

Construction time and inauguration

Calculations of the future demand for drinking and service water for the growing Ruhr area in 1904 had shown that three times as much would be required of the existing dams in the Ruhr river system with a storage volume of 32.4 million m³, namely about 100 million m³ of storage space . By 1925 it was even estimated that it would have grown to almost 200 million m³. Therefore, on November 28, 1904, the general assembly of the Ruhrtalsperrenverein decided to change the statutes to build their own dams. On May 22nd, 1905, the plan to build a large dam in the Möhnetal was discussed for the first time. The Möhnetalsperre was then built between 1908 and 1912 according to plans by the government master builder Ernst Link and based on a design by the Cologne architect Franz Brantzky for the dam at a cost of 23.5 million marks and inaugurated on July 12, 1913 by the Ruhrtalsperrenverein. In the year of its inauguration, the dam was the largest dam in Europe. The former place Kettlersteich sank completely in the water. Most of the village of Delecke (Alt-Delecke) was also flooded. 140 farmsteads with 700 people had to give way to the lake.

Dam burst due to bombing in World War II

Schematic representation of the dropping of a roll or rotation bomb to destroy a dam
Dam heavily damaged by the bombing with blocking balloons to ward off enemy aircraft (1943)
Aerial photo by the Royal Air Force shows the part of the lake near the dam with the heavily damaged dam and a flooded area in the Möhne Valley

The Möhnetalsperre was in World War II by an Operation Chastise ( German  corporal punishment ) mentioned British bombing raid, led by Wing Commander Guy Gibson , in the night of 16 on May 17, 1943 severely damaged.

In order to bypass the defensive systems at the reservoir, roll bombs of the Avro Lancaster type Avro Lancaster from No. 617 Squadron dropped. These roll bombs jumped over the water at a shallow angle due to their rapid rotation and jumped over the torpedo interception nets. They then hit the dam, their twist ensuring that they quickly sank to the bottom of the wall, where they then exploded at a depth of 10 to 15 meters. One of several bombs dropped in quick succession reached its destination and damaged the wall. The storage space was full at the time of the bombing raid in May 1943. This initially resulted in a small crack, which quickly expanded due to the pressure of the outflowing water masses and finally resulted in a trapezoidal gap 77 m wide and 22 m deep.

As a result of the resulting tidal wave , which poured over the Möhne into the Ruhr Valley, according to various sources, at least 1284 or even more than 1600 people died. The fatality in connection with the tidal wave furthest away from the dropping point occurred in Essen-Steele , over 100 kilometers beyond the dam. A memorial at the former Himmelpforten monastery today commemorates the dead in the catastrophe. Neheim, today a district of Arnsberg, was hit particularly hard; the tidal wave was over 12 meters high there. Most of the people died in the Möhnewiesen forced labor camp in Neheim . In Neheim there is another memorial in front of St. John's Church.

The purpose of this attack, in which the Edertalsperre and the Sorpesee were attacked at the same time , was indirectly to impair the armaments industry in the Ruhr area; the Sorpedamm was hardly damaged due to its special concrete construction with earth and stone cover.

The attack on the dam was portrayed in the 1954 British film May '43 - The Dam Busters by Michael Anderson .

reconstruction

Dam wall

The reconstruction of the dam wall with a contingent of several thousand workers around the clock and using the original building materials was initiated immediately after the severe damage, in spite of the very tense general material and strength situation at the time and was able to start on October 3, 1943 with the Application of the road surface on the dam crest should be completed. The rapid progress of the work was ultimately also exploited by the Nazi propaganda to demonstrate at least small successes to the war-weary population. The impact of the attack on the war economy in the Ruhr area was not as lasting as the Allies had originally hoped. They did not attack the large construction site or the then completed dam until the end of the war.

Redevelopment

From 1972 to 1979 the Möhne Reservoir was extensively renovated. By blasting was placed along the bed foundation of the dam a control passage to, from which the wall is pressed and with drainage holes was provided.

The ravages of time also gnawed at the masonry on the free side of the dam. Water penetrated the masonry through the cracks, and the onset of frost damaged stones. In the resulting cavities, seeds accumulated, germinated and formed trees and shrubs, which further damaged the wall with its roots. From 1992 to 2000 extensive renovation work was carried out on the approximately 2.5 hectare air side. Since stone and joint renovations could only be carried out in the summer half of the year, the renovation took eight years.

As with many other reservoirs, relics from days gone by can be found below the surface of the water. In the late summer of 2003, due to repair work on the gate valves in the Hev fore basin, the water level had to be lowered until the Hev basin was completely empty. The old bridge appeared with the road running over it.

The dam wall is entered as a monument in the list of monuments of the municipality of Möhnesee.

Appreciation of the building

Century lights 2013

On the occasion of the 100th anniversary of the completion of the dam in 1912, Deutsche Post AG issued a special postage stamp to the value of 90 euro cents with special postmarks and the text 100 years of Möhne dam on the first day of issue on April 4, 2013 . The design comes from the graphic designers Gerda M. and Horst F. Neumann from Wuppertal .

In 2013 the novel Nachtauge by Titus Müller will be published , which realistically and impressively brings the history of Neheim and the flood disaster from the perspective of historical or fictional characters to life and honors it with readings on site.

For the anniversary, a large number of light installations were exhibited around the compensation pond for one month under the motto of the century lights. The central element was a video installation which, on 160 × 40 meters of the quarry stone surface of the dam between the towers, used slide and video projectors to summarize 100 years of German history with the dam at the center. It was created by Britta and Wolfgang Flammersfeld.

Pulpit Bridge

The pulpit bridge

The Kanzelbrücke, built in 1912, stands over the inlet area of ​​the Möhne in the Möhne foothills, west of Völlinghausen. The building owes its name to the design of its bridge piers, which have a certain resemblance to church pulpits - there are a total of 12 pulpits. The bridge consists of five arches and has a total length of 60 meters. It was badly damaged in the Second World War and was restored to its original state in 1953. The bridge is a replacement for a previous structure with three arched stone arches, which made it possible to cross the Möhne even before the reservoir was built. The building is owned by the Ruhrverband .

Möhneseeturm

Möhneseeturm

Above the Möhnsee, about one kilometer south of the Körbeck pedestrian bridge over the reservoir, stands the 42.5-meter-high Möhneseeturm. The observation tower, which costs around 500,000 euros, was erected in the summer and autumn of 2014 in an exposed location on one of the highest points near the Möhnesee. It was released in mid-December 2014; its official opening took place on May 5, 2015. The Rennweg and the Sauerland forest route lead directly past the tower with a shared route .

The viewing platform offers views of the reservoir, many parts of the municipality of Möhnesee, parts of the Arnsberg Forest nature park and over to the Haarstrang ridge . On a clear day, the view extends to the north into the Westphalian Bay to the Teutoburg Forest and to the south to the heights of the Lennegebirge .

gallery

  • The Kanzelbrücke at the inlet of the Möhne into the Möhnesee

  • Photo of the Möhnese lake and the dam wall from the air

  • The Möhnetalsperre in August 2015

  • Möhnesee dam 2014

  • Level with display of height and filling quantity

  • Water level in September 2018, reservoir half full

  • Revision work on the dam

See also

literature

  • Ralf Blank : The “Möhne catastrophe” in May 1943 as part of European war commemoration. In: Der Märker 61 (2012), pp. 97–121.
  • Ralf Blank: "Ruhr Battle". The Ruhr area in the war year 1943. Essen 2013, here especially pp. 179–184.
  • Helmuth Euler : “When Germany's dams broke. The truth about the bombing of the Möhne-Eder-Sorpe dams in 1943 ”. Motorbuch, Stuttgart, 1975, ISBN 3-87943-367-4 .
  • Helmuth Euler: "Water War - May 17, 1943. Roll bombs against the Möhne-Eder-Sorpe dams". Self-published, Werl 1992, ISBN 3-89053-045-1 .
  • Wilfried Stichmann, Ursula Stichmann-Marny: The Möhnesee. A water bird paradise through the ages. Heimatverein Möhnesee, 2008.
  • Heinrich Zimmer: The Möhne Reservoir. With seven illustrations based on original photographs. In: Reclams Universum: Moderne Illustrierte Wochenschrift 27.1 (1911), pp. 367-370.

Others:

  • Peter Franke, Wolfgang Frey: Dams in the Federal Republic of Germany. Systemdruck, Berlin 1987, ISBN 3-926520-00-0 .

Movies

Individual evidence

  1. ↑ a b c Construction of the Möhnetalsperre. moehne.net, accessed June 19, 2017.
  2. ↑ a b c d e f g h i j k l m n o p q r Technical details: Möhne dam. Ruhrverband, accessed on June 19, 2017.
  3. ↑ a b c d e f g h Storage or storage spaces (in millions of m³ ; according to individual records : → Technical details: Möhnetalsperre ):
    Möhnesee: 126.05 (main barrier), Möhn fore basin: 7, Hev fore basin: 0.8, compensation pond: 0 , 65; Total: 134.5
  4. ^ Friedrich Kühne: Geological map of North Rhine-Westphalia, sheet 4514 Möhnesee, map with explanations. Krefeld 1977, ISBN 3-86029-151-3
  5. ↑ Essen-Grünsand-Formation ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Lithostratigraphic Lexicon of the Federal Institute for Geosciences and Raw Materials, accessed on December 15, 2013. @1@ 2Template: Webachiv / IABot / litholex.bgr.de
  6. ↑ Erwitte-Formation ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Lithostratigraphic Lexicon of the Federal Institute for Geosciences and Raw Materials, accessed on December 15, 2013. @1@ 2Template: Webachiv / IABot / litholex.bgr.de
  7. ↑ Büren formation ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , Lithostratigraphic Lexicon of the Federal Institute for Geosciences and Raw Materials, accessed on December 15, 2013. @1@ 2Template: Webachiv / IABot / litholex.bgr.de
  8. ↑ Oerlinghausen formation ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , Lithostratigraphic Lexicon of the Federal Institute for Geosciences and Raw Materials, accessed on December 15, 2013. @1@ 2Template: Webachiv / IABot / litholex.bgr.de
  9. ↑ Construction and renovation measures at the Möhne dam. ( Memento from December 3, 2013 in the Internet Archive ), on archive.org, Ruhrverband (PDF file; 35 kB).
  10. ↑ Silvia Gängler: century lights on the dam of the Möhnesee. (No longer available online.) In: Arnsberg Neheim Hüsten News, neheim-huesten.de. Gängler Datenservice, May 4, 2013, archived from the original on December 22, 2016 ; accessed on December 21, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / neheim-huesten.de
  11. ↑ Möhneseeturm released ( Memento from December 21, 2014 in the Internet Archive ), on archive.org, Soest district, from December 16, 2014.
  12. ↑ Möhneseeturm is taking shape ( Memento from December 21, 2014 in the Internet Archive ), on archive.org. October 28, 2014
  13. ↑ Möhnesee tower on Rennweg in the Arnsberg Forest officially opened ( Memento of the original from June 17, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , Soest district, on May 5, 2015, accessed on June 17, 2015. @1@ 2Template: Webachiv / IABot / m.kreis-soest.de
  14. ↑ 360-degree panorama from the Möhneseeturm (labeling of visual targets can be activated), panorama-photo.net, accessed on September 6, 2015.

Web links

Commons : Möhnesee (Stausee)  - Collection of images, videos and audio files
Wikivoyage: Möhne Reservoir  - travel guide