Lena

Lena (Evenki, Ölüöne; Yakut, Ulakhan-Yuryakh – big river) – a river in eastern Siberia, one of the great rivers of Russia and the globe. By water content it is the sixth largest in the world. The length is 4,400 km; the basin area is 2,490,000 km². It flows through the Irkutsk region and the Republic of Sakha (Yakutia). The L. originates from a small lake on the western slope of the Baikal Mountains and runs into the Laptev Sea at 73°N. The L. basin is located in taiga and tundra and a small portion north of 71°N in forest tundra. Permafrost soils are widely spread.

According to the nature of the valley and the riverbed, the Lena is divided into three major areas: the upper, from the source to the inflow to the Vitim; the middle, between the mouths of the Vitim and the Aldan; and the lower, from the inflow to the Aldan to the mouth of the Lena. The upper Lena is rapid mountain river flowing through a deeply incised narrow valley with rocky shores and rock cliffs closing to the water,...