LENA RIVER

major river of Russia and one of the longest rivers in the world. It flows 2,734 miles (4,400 km) from its source in a small Siberian mountain lake west of Lake Baikal in Central Asia, northward across Russia, to the mouth of its delta on the Arctic Laptev Sea. The Lena River basin covers an area of about 961,000 square miles (2,490,000 square km). Its major tributaries include the Vitim, Aldan, Great Patom, Olyokma, and Nyuya rivers. Three main sections form the Lena, each about 900 miles (1,450 km) long: the upper section flows from the source to the Vitim tributary; the middle course from the Vitim to the mouth of the Aldan; and the lower section from the Aldan to the Laptev Sea. The river's upper section flows through a deeply cut valley that gradually widens, becoming a large, deep riverbed in the upper half of the middle course. The surrounding slopes are gentle and green with forests, and there is a large water meadow in which many small lakes are scattered. The character of the valley changes sharply in the lower half of the middle course. There the Lena flows along the bottom of a narrow valley with sheer, broken slopes; the area is a popular site for tourists and rock climbers. In the lower section, as the Lena enters the Yakut Lowland, the riverbed widens and water meadow abounds once again. The climatic conditions of the Lena basin are determined by its continental location. Air temperatures in the winter are severe, the average monthly figure in January being -22 to -40 F (-30 to -40 C). In July temperatures range between 50 and 68 F (10 and 20 C). Because of its remoteness from the sea, the amount of precipitation in the basin is slight, falling mainly in the summer; on the average no more than 2 inches (50 mm) of snow fall each year. Typical of the Lena basin are high floods, especially flash floods, in the summer, and very little flow in the winter. The average annual discharge is 579,000 cubic feet (16,400 cubic m) per second. In some locations the riverbed and floodlands are covered with permanent ice. A large part of the basin is covered with taiga (swampy northern coniferous forest); tundra is found along the lower course near the Arctic. Farms produce cereal crops and raise livestock on the Yakut Lowland. The basin is rich in coal and natural gas, and gold occurs in exploitable quantities. Yakutsk is the chief city among many industrial centres on the Lena, and Osetrovo is the river's leading modern port. The Lena River basin and its drainage network. major river of Russia and the 10th longest river in the world. It flows 2,734 miles (4,400 kilometres) from its sources in the mountains rising along the western shores of Lake Baikal, in southeastern Siberia, to the mouth of its delta on the Arctic Laptev Sea. The area of the river basin is about 961,000 square miles (2,490,000 square kilometres). Additional reading The Lena River is described in broad geographic surveys of North Asia that provide information on physical features and on economic, social, and cultural conditions: Paul E. Lydolph, Geography of the U.S.S.R., 5th ed. (1990); Michael T. Florinsky (ed.), McGraw-Hill Encyclopedia of Russia and the Soviet Union (1961), with short articles on the individual rivers; S.V. Kalesnik and V.F. Pavlenko (eds.), Soviet Union: A Geographical Survey (1976; originally published in Russian, 1972); and Great Rivers of the World (1984), published by the National Geographic Society. M.I. L'vovich, Reki SSSR (1971), is a well-known work treating the hydrologic characteristics of the main rivers of the former U.S.S.R. Lev Konstantinovich Davydov, Gidrografiia SSSR, vol. 2 (1955), provides detailed studies of regional hydrology and hydrography. G.V. Voropaev and A.B. Avakian (eds.), Vodokhranilishcha i ikh vozdeistvie na okruzhaiushchuiu sredu (1986), examines the influence of water reservoirs on the environment. Schemes for large-scale water transfer are described in two articles by Philip P. Micklin: The Vast Diversion of Soviet Rivers, Environment, 27(2):1220, 4045 (March 1985), and The Status of the Soviet Union's North-South Water Transfer Projects Before Their Abandonment in 198586, Soviet Geography, 27(5):287329 (May 1986). Philip P. Micklin