Lake Vänern landscape (LTSER) - Sweden

Lake Vänern is the largest freshwater body in Sweden and the largest lake within the European Union with a 5 650 km2 water surface, a drainage basin covering a total of 46 800 km2, a coastline of 4 800 km and a freshwater archipelago made up of over 22 000 islands, islets and rocks. The lake contains one third of Sweden?s freshwater reserve. Lake Vänern is situated in the south west part of Sweden and is connected to the North Sea via the Kattegat coastal region. The only outlet from the lake to Skagerrak is via the Göta River. The lake itself lies in the middle of a water system that is 720 km long and has its sources of the watershed in northern Sweden and in the neighboring districts in Norway in Lake Rogen. From there the water flows via the Klarälv River into Lake Vänern. The Värmlandssjön is the larger of the two basins in Lake Vänern. It is also large enough for geostrophic currents to occur anticlockwise throughout the summer. Vertical water transports within the basins are of little importance apart from in spring and autumn when the water masses are mixed and also intermixed between the basins. In summer a thermocline is established together with a warm water zone at the margins of the lake´s shallow regions.