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a river in central Sweden. The Ljusnan is 430 km long and drains an area of 19,800 sq km. Rising in the Scandinavian Mountains near the Swedish-Norwegian border, it crosses the southern Norrland Plateau, flows through a series of lakes, forming numerous rapids and waterfalls, and empties into the Gulf of Bothnia of the Baltic Sea. It is fed mainly by snow. The mean flow rate is 230 cu m per sec. The river freezes over for six or seven months a year. It is used for timber flotation. A hydroelectric power plant with a total capacity of 430 megawatts is located on the Ljusnan.