Lake Thun (German: Thunersee) is an Alpine lake in the Bernese Oberland in Switzerland named after the city of Thun, on its northern shore. At 48.3 km2 (18.6 sq mi) in surface area, it is the largest Swiss lake entirely within a single canton.

Lake Thun
Thunersee
Aerial view of Lake Thun
Lake Thun Thunersee is located in Canton of Bern
Lake Thun Thunersee
Lake Thun
Thunersee
Lake Thun Thunersee is located in Switzerland
Lake Thun Thunersee
Lake Thun
Thunersee
Lake Thun Thunersee is located in Alps
Lake Thun Thunersee
Lake Thun
Thunersee
LocationCanton of Bern
Coordinates46°41′N 7°43′E / 46.683°N 7.717°E / 46.683; 7.717
Typefreshwater fjord, recent regulation[1]
Primary inflowsAare
Kander
Primary outflowsAare
Catchment area2,500 km2 (970 sq mi)
Basin countriesSwitzerland
Max. length17.5 km (10.9 mi)
Max. width3.5 km (2.2 mi)
Surface area48.3 km2 (18.6 sq mi)
Average depth136 m (446 ft)
Max. depth217 m (712 ft)
Water volume6.5 km3 (5,300,000 acre⋅ft)
Residence time684 days
Surface elevation558 m (1,831 ft)
SettlementsThun, Spiez, Faulensee
Map

The lake was created after the last glacial period. After the 10th century, it split from Lake Brienz, before which the two lakes were combined, as Wendelsee ("Lake Wendel").[2] The culminating point of the lake's drainage basin is the Finsteraarhorn at 4,274 metres (14,022 ft) above sea level.[3]

Lake Thun's approximate 2,500 square kilometres (970 sq mi) catchment area frequently causes local flooding after heavy rainfalls. This occurs because the river Aare (German: Aare), which drains Lake Thun, has only limited capacity to handle the excess runoff. The lake is fed by water from Lake Brienz to the southeast, which is 6 metres (20 ft) higher than Lake Thun, and various streams in the Oberland, including the Kander.

In 1835, passenger steamships began operating regularly on the lake. Ten passenger ships, operated by the local railway company BLS AG like Blümlisalp, serve the towns of Interlaken and Thun; the Interlaken ship canal and Thun ship canal connect the lake to Interlaken West railway station and Thun railway station respectively.[4][5]

Following World War II and up until 1964, the Swiss Government disposed of unused munitions into Lake Thun. The quantity of munitions dumped is reported to be from 3,000 to more than 9,020 tons.[6][7]


Lake Thun (left) and Lake Brienz on the Swiss National Map (1:25'000)

References

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  1. ^ Kanton Bern, Wasser- und Energiewirtschaftsamt (Water and Energy Department): Möglichkeiten und Grenzen der Seeregulierung am Thuner See (Possibilities and limits of regulating the Thunersee)[permanent dead link]
  2. ^ www.spiez.ch: Schloss (Castle of) Spiez around 1000 AD called "Goldener Hof am Wendelsee" ("Golden Court on lake Wendel) Archived 2014-05-14 at the Wayback Machine
  3. ^ 1:25,000 topographic map (Map). Swisstopo. Retrieved 2014-07-28.
  4. ^ "History of navigation on Lakes Thun and Brienz". BLS AG. Retrieved 2012-12-13.
  5. ^ "BLS Schiffahrt - Our fleet". BLS AG. Retrieved 2012-12-13.
  6. ^ Foulkes, Imogen (August 28, 2003). "Fears over dumped munitions in Lake Thun". Retrieved March 19, 2010.
  7. ^ Tagliabue, John (August 12, 2009). "A Turbulent Past Lurks in a Serene Swiss Lake". NYTimes.com. Retrieved Sep 13, 2009.
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