Швециядағы ең ірі көл – Венерн

Largest lake in Sweden

Vänern ('/v//eɪ//n//ər//n/ VAYnərn, /USalso/'/v//ɛ//n//ər//n/ VENərn, ) is the largest lake in Sweden, the largest lake in the European Union and the third largest lake in Europe after Ladoga and Onega in Russia. It is located in the provinces of Västergötland, Dalsland, and Värmland in the southwest of the country. With its surface located at with a maximum depth of , the lowest point of the Vänern basin is at below sea level. The average depth is at a more modest , which means that the average point of the lake floor remains above sea level. Vänern drains into Göta älv towards Gothenburg and the Kattegat tributary of the Atlantic Ocean. It is the only one of the ten largest lakes in Sweden not to drain on the country's eastern coastline. Due to the construction of Göta Canal in the 19th century, there is an upstream water path to Vättern and the east coast from Vänern. The main inflow of water comes from Klarälven entering Vänern near Karlstad with its source in Trøndelag in Norway.

The southeastern part of the Vänern is a depression that appears to have come into being by erosion of Paleozoic aged sedimentary rock during the Quaternary glaciation that reached to the area. Because the southern and eastern shores are parts where the Sub Cambrian peneplain gently tilts towards the north and west, respectively, the lake is rather shallow at these places. As a result, there are still species remaining from the ice age not normally encountered in freshwater lakes, such as the amphipod Monoporeia affinis. A Viking ship was found on the lake's bottom on May 6, 2009. A story told by the 13th century Icelandic mythographer Snorri Sturluson in his Prose Edda about the origin of Mälaren was probably originally about Vänern: the Swedish king Gylfi promised a woman, Gefjon, as much land as four oxen could plough in a day and a night, but she used oxen from the land of the giants, and moreover uprooted the land and dragged it into the sea, where it became the island of Zealand. The Prose Edda says that 'the inlets in the lake correspond to the headlands in Zealand'; since this is much more true of Vänern, the myth was probably originally about Vänern, not Mälaren. The Battle on the Ice of Lake Vänern was a 6th century battle recorded in the Norse sagas and referred to in the Old English epic Beowulf. In Beowulf, Vänern is stated to be near the location of the dragon's mound at Earnaness.

Vänern covers an area of , approximately twice the surface area of Luxembourg. Its surface is above sea level and it is on average deep. The maximum depth of the lake is The water level of the lake is regulated by the Vargön Hydroelectric Power Station. Geographically, it is situated on the border between the Swedish regions of Götaland and Svealand, divided between several Swedish provinces: The western body of water is known as the Dalbosjön, with its main part belonging to Dalsland; the eastern body is known as Värmlandsjön, its northern part belonging to Värmland and the southern to Västergötland. Its main tributary is Klarälven, which flows into the lake near the city of Karlstad, on the northern shore. Other tributaries include Gullspångsälven, Byälven and Norsälven. It is drained to the south west by Göta älv, which forms part of the Göta Canal waterway, to Lake Viken into Lake Vättern, southeast across Sweden. The economic opportunities Vänern offers are illustrated by the surrounding towns, which have supported themselves for centuries by fishing and allowing easy transportation to other cities or west by Göta älv to the sea of Kattegat. This directly includes: Karlstad (chartered in 1584), Kristinehamn (1642), Mariestad (1583), Lidköping (1446) Vänersborg (1644), Åmål (1643), Säffle (1951), and indirectly Trollhättan (1916). The Djurö archipelago surrounds the island of Djurö, in the middle of the lake, and has been given national park status as Djurö National Park. The ridge (plateau mountain) Kinnekulle is a popular tourist attraction near the south eastern shore of Vänern. It has the best view over the lake (about above the lake level). Another nearby mountain is Halleberg.

Environmental monitoring studies are conducted annually. In a 2002 report, the data showed no marked decrease in overall water quality, but a slight decrease in visibility due to an increase of algae. An increasing level of nitrogen had been problematic during the 1970s through 1990s, but is now being regulated and is at a steady level. Some bays also have problems with eutrophication and have become overgrown with algae and plant plankton.

The most common birds near Vänern are terns and gulls. Great cormorants have returned and are flourishing. This has contributed to the increase in the population of white tailed sea eagles, who feed on cormorants.