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Tinnsjø / Tinnsjøen
Tinnsjo - Norway.jpg
View of the lake
Norway Vestfold og Telemark adm location map.svg
Red pog.svg
Location of the lake
Relief Map of Norway.png
Red pog.svg
Tinnsjå (Norway)
Tinnsjå's primary sources are Måna and Mår
Location Tinn Municipality,
Vestfold og Telemark
Coordinates 59°58′34″N8°48′56″E / 59.97612°N 8.81542°E / 59.97612; 8.81542
Primary inflows Måna river
Primary outflows Tinnelva river
Basin  countries Norway
Max. length35 km (22 mi)
Max. width5 km (3.1 mi)
Surface area51.56 km2 (19.91 sq mi)
Average depth189 m (620 ft) [1]
Max. depth460 m (1,510 ft) [1]
Water volume9.71  km3 (2.33  cu mi) [1]
Surface elevation191 m (627 ft)
ReferencesSeppälä; [1] NVE [2]

Tinnsjå (also known as Tinnsjø or Tinnsjøen; English: Lake Tinn [3] [4] [5] ) is one of the largest lakes in Norway measuring about 51.56-square-kilometre (19.91 sq mi). It is also one of the deepest lakes in Europe, reaching a depth of 460 metres (1,510 ft). Tinnsjå is located in the municipalities of Tinn and Notodden in Vestfold og Telemark county. At its source in the west, the Måna river flows out of the lake Møsvatn and past the town of Rjukan into Tinnsjå. From the north, the river Mår flows from the lakes Mår, Gøystavatn, and Kalhovdfjorden into Tinnsjå. Tinnsjå is part of the Skien watershed, and it drains via the Tinnelva river in the south, down to the lake Heddalsvatn. [6]


At the north end of the lake lie the villages of Atrå and Austbygdi. The village of Miland lies on the western shore of the lake. The village of Hovin lies up on a hill overlooking the eastern shore of the lake and the village of Rudsgrendi lies on the western shore. There is a small dam at the south end of the lake which regulates the surface elevation of the lake and the village of Tinnoset is located at this end of the lake. The village of Gransherad lies about 4 kilometres (2.5 mi) south of this dam. [6]


In 1944, during the German occupation of Norway, the ferry SF Hydro was sunk in Tinnsjå by the Norwegian resistance. The Germans were using the ferry to transport a large quantity of heavy water to Germany, where it was to be used for nuclear weapons research. The heavy water had been produced at Vemork, a factory located in Rjukan.

The wreck of the ferry was discovered in 1993. [7] In 2004, it was investigated and filmed for an episode of NOVA; heavy water samples were recovered and deuterium isotopic enrichment was confirmed.

In 2004, a film crew shooting footage for a new documentary on the heavy water sabotage became aware of an unusual fish, swimming near the lake bottom at a depth of 430 metres (1,410 ft). Two specimens of the previously unknown fish were captured in April 2005. Analysis revealed the fish to be closely related to Arctic char. The light-colored, translucent fish is up to 15 centimetres (5.9 in) long and lacks a swim bladder. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Tinn</span> Municipality in Telemark, Norway

Tinn is a municipality in Vestfold og Telemark county, Norway. It is located in the traditional districts of Aust-Telemark and Upper Telemark. The administrative centre of the municipality is the town of Rjukan. Some of the villages in Tinn include Atrå, Austbygde, Hovin, and Miland.

<span class="mw-page-title-main">Rjukan</span> Town in Tinn, Norway

Rjukan is a town in Tinn Municipality in Vestfold og Telemark county, Norway. The town is also the administrative centre of Tinn Municipality. The town is located in the Vestfjorddalen valley, between the lakes Møsvatn and Tinnsjå. The municipal council of Tinn declared town status for Rjukan in 1996. The town is located about 10 kilometres (6.2 mi) to the west of the village of Miland and about 20 kilometres (12 mi) to the northwest of the village of Tuddal.

<span class="mw-page-title-main">Norwegian heavy water sabotage</span> Sabotage operations with the aim of halting the creation process of Nazi nuclear weapons

The Norwegian heavy water sabotage was a series of Allied-led efforts to halt German heavy water production via hydroelectric plants in Nazi Germany-occupied Norway during World War II, involving both Norwegian commandos and Allied bombing raids. During the war, the Allies sought to inhibit the German development of nuclear weapons with the removal of heavy water and the destruction of heavy-water production plants. The Norwegian heavy water sabotage was aimed at the 60 MW Vemork power station at the Rjukan waterfall in Telemark.

<span class="mw-page-title-main">Hornindalsvatnet</span> Lake in Norway, and Europes deepest lake

Hornindalsvatnet is Norway's and Europe's deepest lake, and the world's thirteenth deepest lake, officially measured to a depth of 514 metres (1,686 ft). Its surface is 53 metres (174 ft) above sea level, which means that its bottom is 461 metres (1,512 ft) below sea level.

<span class="mw-page-title-main">Vemork</span> Hydroelectric power plant in Norway

<span class="mw-page-title-main">Miland</span> Village in Tinn, Norway

Miland is a village in Tinn Municipality in Vestfold og Telemark county, Norway. The village is located in the Vestfjorddalen valley, near the western shore of the large lake Tinnsjå, about 11 kilometres (6.8 mi) east of the town of Rjukan, about 10 kilometres (6.2 mi) south of the village of Atrå, and about 10 kilometres (6.2 mi) to the southwest from the village of Austbygde.

<span class="mw-page-title-main">Rjukan Falls</span> Waterfall in Vestfold og Telemark, Norway

Rjukan Falls (English) or Rjukanfossen (Norwegian) is a waterfall in the western part of the Vestfjorddalen valley in Tinn Municipality in Vestfold og Telemark county, Norway. The 104-metre (341 ft) tall waterfall is located on the river Måna, about 5 kilometres (3.1 mi) to the west of the town of Rjukan.

<span class="mw-page-title-main">Møsvatn</span> Lake in Telemark, Norway

Møsvatn or Møsvann is a lake in Vinje Municipality in Vestfold og Telemark county, Norway. It is the tenth-largest lake in Norway with a surface area of 79.1 square kilometres (30.5 sq mi) and a volume of 1,573,523,000 cubic metres (1,275,676 acre⋅ft). The lake lies just east of the Hardangervidda National Park, in Skien watershed (Skiensvassdrag) catchment area. The lake discharges into the Måna river at a dam located on the Vinje-Tinn municipal border. The lake has an irregular shape with three arms. The longest length across the lake is about 40 kilometres (25 mi). Møsvatn is a shallow mountain lake by Norwegian standards, reaching a maximum depth of 68.5 metres (225 ft).

<span class="mw-page-title-main">Rjukan Line</span> Railway line in Vestfjorddalen, Norway

The Rjukan Line, at first called the Vestfjorddal Line, was a 16-kilometre (10 mi) Norwegian railway line running through Vestfjorddalen between Mæl and Rjukan in Vestfold og Telemark county. The railway's main purpose was to transport chemicals from Norsk Hydro's plant at Rjukan to the port at Skien, in addition to passenger transport. At Mæl the wagons were shipped 30 kilometres (19 mi) on the Tinnsjø railway ferry to Tinnoset where they connected to the Tinnoset Line. The Rjukan Line and the ferries were operated by Norsk Transport, a subsidiary of Norsk Hydro.

<span class="mw-page-title-main">Tinnoset Line</span> Norwegian railway line

The Tinnoset Line was a 30-kilometer (19 mi) long Norwegian railway line that went from Tinnoset to Notodden in Vestfold og Telemark county. The railway was part of the transport chain used to transport fertilizer from Norsk Hydro's factory in Rjukan to the port in Skien. The railway opened in 1909 and was closed when the plant closed in 1991. The railway is sometimes mistakenly believed to be part of the Rjukan Line.

<span class="mw-page-title-main">Tinnsjø railway ferry</span>

Tinnsjø railway ferry was a Norwegian railway ferry service on Lake Tinn that connected the Rjukan Line and Tinnoset Line. The 30-kilometer (19 mi) long ferry trip made it possible for Norsk Hydro to transport its fertilizer from the plant at Rjukan to the port in Skien. The ferry services were operated by the company's subsidiary Norsk Transport from 1909 to 1991, when the plant closed.

SF <i>Hydro</i> Norwegian steam powered railway ferry

SF Hydro was a Norwegian steam powered railway ferry that operated in the first half of the 20th century on Lake Tinn in Telemark. It connected with the Rjukan Line and Tinnoset Line, at Mæl and Tinnoset, operating between 1914 and 1944. The combined track and ferry service was primarily used to transport raw materials and fertilizer from Norsk Hydro's factory at Rjukan to the port in Skien. It was the target of a Norwegian operation on 20 February 1944, when resistance fighters sank the ferry in the deepest part of Lake Tinn to prevent Nazi Germany from receiving heavy water.

<span class="mw-page-title-main">Mæl Station</span> Railway station in Tinn, Norway

Mæl Station is a railroad station located at Tinn in Telemark, Norway. It is the terminus of the Rjukan Line (Rjukanbanen) running through Vestfjorddalen between Mæl and Rjukan. The station is located 16 km from Rjukan and on the mouth of the river Måna in Vestfjorddalen where the river runs into Lake Tinn. This was the point where the railway cars on the line were transferred to the Tinnsjø railway ferry for transport to the Tinnoset Line.

<span class="mw-page-title-main">Vestfjorddalen</span> Valley in Telemark, Norway

Vestfjorddalen is a valley in Tinn Municipality in Vestfold og Telemark county, Norway. The 30-kilometre (19 mi) long valley stretches from the lake Tinnsjå westwards past Rjukan, Vemork, and Rjukan Falls to the lake Møsvatn in the west. The Måna River runs through the entire valley. The west end of the valley begins at the lake Møsvatn where the valley is quite wide. The river Måna is dammed in this area, creating the Skardfoss lake. Just below the dam lies the Rjukan Falls and the Vemork power plant. Just before the falls is where the valley narrows considerably and forms a gorge. After the power plant, the valley remains very narrow, with mountains on both sides reaching 700–800 metres (2,300–2,600 ft) in height. The mountain Gaustatoppen lies along the south side of the valley. Due to the steep mountainsides along the south side of the valley, the sun is unable to reach much of the valley floor throughout the winter.

<span class="mw-page-title-main">Måna</span> River in Telemark, Norway

The Måna or Måne is a river in Tinn Municipality in Vestfold og Telemark county, Norway. The 32-kilometre (20 mi) river flows from the lake Møsvatn through the Vestfjorddalen valley and the town of Rjukan to the large lake Tinnsjå near the village of Miland. It is part of the Skiensvassdraget drainage basin.

<span class="mw-page-title-main">Norwegian Industrial Workers Museum</span> Industrial museum in Rjukan, Norway

Norwegian Industrial Workers Museum is an industrial museum located at Rjukan in Tinn, Norway. Located in the Vemork power station, it was established in 1988 to allow the preservation of industrial society created by Norsk Hydro when they established themselves in Rjukan in 1907. The museum is an anchor point on the European Route of Industrial Heritage.

<span class="mw-page-title-main">Norsk Hydro Rjukan</span>

Norsk Hydro Rjukan is an industrial facility operated by Norsk Hydro at Rjukan in Tinn, Norway, from 1911 to 1991. The plant manufactured chemicals related to the production of fertilizer, initially potassium nitrate from arc-produced nitric acid and later ammonia, hydrogen, and heavy water. The location was chosen for its vicinity to hydroelectric power plants built in the Måna river.

<span class="mw-page-title-main">Kalhovdfjorden</span> Lake in Telemark, Norway

Kalhovdfjorden is a lake in Tinn Municipality in Vestfold og Telemark county, Norway. The lake lies about 20 kilometres (12 mi) to the north of the town of Rjukan and about 15 kilometres (9.3 mi) east of the Hardangervidda National Park. The lake is part of the Skien watershed. The river Mår is the main outflow of the lake. The lake Møsvatn lies to the southwest and the lake Tinnsjå lies to the southeast. The area of the lake is 20.39 square kilometers (7.87 sq mi) and it is located 1,084 meters (3,556 ft) above sea level.

Knut Lier-Hansen was a Norwegian resistance member during World War II. He was born and grew up in Rjukan. Around 1940 he was a sergeant in the Norwegian Army, and tried to repel the German invaders in April 1940, among others in a skirmish at Gransherad. He later joined the more irregular resistance movement. His most notable mission was the sinking of SF Hydro as a part of the Norwegian heavy water sabotage. After placing explosives below deck in the ferry, the saboteurs had to wait until the ferry's departure in the morning to oversee that nothing went against the plan. After witnessing the ferry leave harbor in a normal way, Lier-Hansen fled the scene for Einar Skinnarland's house. The ferry went down in the middle of Lake Tinn, and in addition to sabotaging the heavy water program, eighteen lives were lost. When the war between Germany and Norway was over, on 8 May 1945, Lier-Hansen was dispatched together with Henry Johansen and another person to arrest Reichskommissar für die besetzten Norwegischen Gebiete Josef Terboven. The Norwegians reached Skaugum where Terboven had entrenched himself, but they were warded off by guards. Soon after, Terboven blew himself up.

<span class="mw-page-title-main">Atrå</span> Village in Tinn, Norway

Atrå is a village in Tinn Municipality in Vestfold og Telemark county, Norway. The village is located at the northwestern end of the large lake Tinnsjå, about 6 kilometres (3.7 mi) to the west of the village of Tinn Austbygd and about 12 kilometres (7.5 mi) to the north of the village of Miland. The village lies along the river Gøyst in the Gøystdalen valley which heads to the northwest from the shore of the lake.


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  2. "Innsjødatabase". nve.no (in Norwegian). Retrieved 17 August 2023.
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  4. Gallagher, Thomas (2010). Assault in Norway: Sabotaging The Nazi Nuclear Program. Guilford, CT: Lyons Press. p. 173.
  5. Mead, William Richard (1965). How People Live in Norway. London: Ward Lock Educational Co. Ltd. p. 43.
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  8. Mathismoen, Ole (11 May 2005). "Ny fisk oppdaget" [New Fish Discovered]. Aftenposten. Retrieved 1 February 2015.