Vänern

Vänern is a massive body of water located in southwest Sweden.

It holds the title of the largest lake in Sweden. It is also the largest lake within the European Union. Across the entire continent of Europe, it ranks as the third-largest lake. Only Ladoga and Onega in Russia are larger. The lake sits within the provinces of Västergötland, Dalsland, and Värmland. Its surface area is approximately 5,650 square kilometers. This is about twice the surface area of Luxembourg.

The lake functions as a major part of a complex water system. The main inflow of water comes from the Klarälven river. This river starts in Trøndelag, Norway, and enters near Karlstad. Other tributaries include the Gullspångsälven, Byälven, and Norsälven. To leave the lake, water drains southwest through the Göta älv. This river flows toward Gothenburg and the Kattegat strait. The Kattegat is an opening between the North Sea and the Baltic Sea.

Additionally, the 19th-century Göta Canal creates a navigable waterway. This canal links the east coast with Vänern.

The lake is divided into distinct geographical parts. The western body of water is called Dalbosjön. This part mostly belongs to the province of Dalsland. The eastern body is known as Värmlandsjön. This area is split between Värmland and Västergötland. The depth of the lake varies significantly across these sections. The surface sits above sea level, but the lowest point in the basin is below sea level. The maximum depth reaches 106 meters. However, the average depth is only about 27 meters.

Geological forces shaped the lake over thousands of years. During the Quaternary glaciation, erosion acted on Paleozoic sedimentary rock. This process re-exposed parts of the Sub-Cambrian peneplain. This peneplain is a large, flat area of ancient rock. Because this surface tilts north and west, the southeast part of Vänern is shallow. The western shore follows a fault scarp from the Vänern-Göta Fault. About 10,000 years ago, the melting ice created a strait between Kattegat and the Gulf of Bothnia. Eventually, Vänern became part of the Ancylus Lake. Further uplifting later cut the lake off from the Baltic Sea.

This history left lasting marks on the local environment. Because of its former connection to the sea, unique species live here. One example is the amphipod Monoporeia affinis.

The lake also holds historical treasures. In May 2009, explorers found a Viking ship on the lake floor. Even ancient myths mention the area. The Prose Edda tells a story about the goddess Gefjon. Some scholars believe this myth was originally about Vänern rather than Mälaren. The inlets in the lake match the headlands of Zealand in the story.

Many different animals thrive in these waters. The most common fish is the smelt, especially in Dalbosjön. There are about 2,600 smelt per hectare in that area. The vendace is the second most common fish. Large species include brown trout and zander. Small fish like the stickleback are also present.

Birds are also very active near the shores. Terns and gulls are the most frequent visitors. Great cormorants have returned and are now flourishing. This has helped the white-tailed sea eagle population grow. These eagles feed on the cormorants.

Humans have long relied on Vänern for survival and travel. Towns like Lidköping and Mariestad have existed for centuries. These communities grew through fishing and easy transportation. The Göta älv allows travel west toward the sea. The lake also supports various industries and tourism. Visitors can explore the Djurö National Park on the central islands.

Others visit the Kinnekulle plateau for its views. This plateau rises about 110 meters above the lake level. Nearby, the mountain Halleberg is another notable landmark. The Vargön Hydroelectric Power Station helps regulate the water levels today.