Klarälven ("The clear river" in Swedish) is a river flowing through Norway and Sweden. Together with Göta älv, which it is called as the river has passed through the lake Vänern, thus regarded as an entity, Göta älv—Klarälven is the longest river in Scandinavia and in the Nordic countries and its Swedish part the longest river of Sweden. These two rivers also have the largest drainage basin in the same areas, including all the rivers that run into Vänern, of which is located in Sweden and in Norway. It emanates at the northeast side of Mount Brändstöten and flows through a couple of smaller lakes down to Lake Rogen in Härjedalen, Sweden, and then passes through the Norwegian Hedmark, where it flows through the lake Femunden. There it is known as Femundelva and Trysilelva. The rest of the river, the longest part, flows through Värmland to ultimately discharge in a delta into Vänern at Karlstad. In its turn, Vänern drains then into Göta älv, reaching the sea at Gothenburg. The river has historically provided significant economic benefits, providing a suitable transport route for log driving, and currently is internationally recognized as excellent sport fishing waters. Geography and geology The watershed of Klarälven is commonly referred to as Klarälvdalen (the Klarälv basin), where it accumulates much of its water on its journey to Vänern. Other important sources of water are the snowy mountains in the northern areas of the watershed area, providing substantial flows in the spring when the snow melts; annual floods are common. The straight river course north of Edebäck has been classified by Sten De Geer as a "tectonic valley" as it follows the Protogine Zone—a bedrock weakness zone of Precambrian age. During deglaciation of Scandinavia about 10,000 years before present the glacier ice retreated unevenly with the valley of Klarälven hosting a protruding ice tongue while the surrounding uplands were ice-free. The retreat of the ice left dead-ice buried in the glacifluvial sediments of the valley. The river course north of Edebäck formed an ancient fjord after it became free of glacier ice and before the post-glacial rebound definitely raised the valley bottom above the sea. The river course south of Edebäck is possibly a Quaternary deflection caused by the accumulation of glacial deposits. Since the end of the last ice age, the mouth of Klarälven has moved southward from Forshaga to its current position at Karlstad,