Luleälven

a river in northern Sweden. Length, 450 km; basin area, 25,200 sq km.

Luleälven rises from Lake Virihaure near the Norwegian border and flows in its upper and middle course primarily in a narrow and deep valley with sections full of rapids and water-falls, crossing a number of lakes. Below the influx of the main right tributary, Lilla Luleälven, the valley widens and Luleälven flows across a hilly plain; it falls into the Gulf of Bothnia in the Baltic Sea. High water occurs in summer, and the water is low in winter; average annual rate of discharge in the lower course is 510 cu m per sec. The flow is regulated by the lakes. The river freezes in late October and thaws in May. There are hydroelectric power plants on the river with a total output of approximately 1.7 gigawatts. (The most important are Harsprånget, Porjus, and Letsi.) Timber is floated, and the lakes are navigated. The seaport of Luleå is near the mouth.