| Võrtsjärv | |
|---|---|
 Lake Võrtsjärv by ariver mouth nearRõngu | |
  Võrtsjärv Location within Europe Show map of Europe.png) Võrtsjärv Location within Estonia Show map of Estonia | |
| Location | Estonia |
| Coordinates | 58°17′N26°02′E / 58.283°N 26.033°E /58.283; 26.033 |
| Primary inflows | Väike Emajõgi Tänassilma Õhne Tarvastu |
| Primary outflows | Emajõgi |
| Catchment area | 3,100 km2 (1,200 sq mi) |
| Basin countries | Estonia,Latvia |
| Surface area | 270 km2 (100 sq mi) |
| Average depth | 2.7 m (8 ft 10 in) |
| Max. depth | 6 m (20 ft) |
| Water volume | 0.8 km3 (650,000 acre⋅ft) |
| Shore length1 | 96 km (60 mi) |
| Surface elevation | 33.7 m (111 ft) |
| 1 Shore length isnot a well-defined measure. | |
Lake Võrtsjärv (Estonian:Võrtsjärv[ˈʋɤrts.jærʋ]lit. 'Võrts lake';[1][2]German:Wirzsee)[3] is alake in southernEstonia with an area of 270 km² (104 mi²).
It is the second largest lake in Estonia (afterLake Peipus),[4] and the largest lake situated entirely within Estonia. The shallow lake is 33.7 m (111 ft) above sea level. TheEmajõgi river flows from Lake Võrtsjärv to Lake Peipus.
The lake basin existed before thelast Ice Age, but was then transformed by moving ice sheets which partly eroded the lake wall and partly filled the depression with deposits. In its present form the lake has existed since theMiddle Holocene.[5]
It was first mentionedc. 1229 in theLivonian Chronicle of Henry, where it is calledWorcegerwe.[6]
The relatively low shores of the lake are swampy in the south and sandy in the north.[7] On the eastern shore, there is a coastal abrasion near the village ofTamme; these cliffs have yielded a number of fossils ofDevonian fish, which have been compared to similar fossils found inScotland.[8]
There are a few smallislands in the southern part of the lake. Of these onlyTondisaar and Pähksaar are permanent islands, while Ainsaar becomesa peninsula during low water and Heinassaar issubmerged at high water.[7] This is because of the lakes fluctuatingwater level, which changes with a mean annual amplitude of 1.4 m; this is about half of its 2.8 m average depth. From around November to April, the lake is covered with an ice sheet.[9]
Situated northeast of the lake is theAlam-Pedja Nature Reserve, the largestnature reserve in Estonia.
Around 35 species of fish are found in the lake, a few of which arecommercially important. After a decline of valuable species during the 1950s and 1960s, some conservation measures were enforced which lead to an improvement in the situation. Today, around 400 t of fish are caught annually.[7]
Lake Võrtsjärv is the main catchment area foreel in Estonia. However, fishing is entirely dependent on restocking with farmedglass eels,[10][11] as eels are migratory and do no longer return in sufficient quantities to Europe. Due to declining numbers of natural eel, in 2017 theEuropean Union's Agriculture and Fisheries Council decided on a three-month ban of eel fishing in theBaltic Sea during eel migratory season. Eel caught in the Baltic Sea had only accounted for a mere 700 kg the year before, as opposed to an average of 10.2-13.3 t per year in Lake Võrtsjärv.[12]
The lake and the nearby wetlands are also an important breeding ground for birds, as well as a staging area formigratory birds. In total, 213 bird species have been recorded around the lake.[9]
In recent decades,eutrophication of the lake has increased, with detrimental effects on biological diversity.[13] This is thought to be mainly caused by a combination of poorly treated wastewater influx as well as phosphorus and nitraterunoff from agriculture. In addition, climatic fluctuations seem to have a stronger influence on the lake due to its shallow depth.[14]
The region is little known as a tourist destination internationally[15] and, especially in the second half of the 20th century, the deteriorating water quality posed a continuous problem for both fishing and tourism development.[9] However, more recently, in 2010, Võrtsjärv was votedEuropean Destination of Excellence.[16]
There is a visitor centre and museum on the east shore of the lake.[17]
In 2016, the lake was the site of the WISSA World Championships iniceboating on the frozen lake.[18]
[...] gelangten endlich an die SeeWorcegerwe, wo sie übers Eis zogen und mit Freuden nach Liefland kehrten.
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