Most geographers divide the vast Soviet territory into five natural zones that generally extend from west to east: the tundra zone; the taiga or forest zone; the steppe or plains zone; the arid zone; and the mountain zone. Most of the Soviet Union consists of three plains (East European Plain, West Siberian Plain, and Turan Lowland), two plateaus (Central Siberian Plateau and Kazakh Upland), and a series of mountainous areas, concentrated for the most part in the extreme northeast or extending intermittently along the southern border. The West Siberian Plain, the world's largest, extends east from the Urals to the Yenisey River (see fig. 6). Because the terrain and vegetation are uniform in each of the natural zones, the Soviet Union, as a whole, presents an illusion of uniformity. Nevertheless, the Soviet territory contains all the major vegetation zones with the exception of tropical rain forest. Ten percent of Soviet territory is tundra, that is, a treeless marshy plain. The tundra is the Soviet Union's northernmost zone of snow and ice, stretching from the Finnish border in the west to the Bering Strait in the east and then running south along the Pacific coast to the earthquake and volcanic region of northern Kamchatka Peninsula. It is the land made famous by herds of wild reindeer, by "white nights" (dusk at midnight, dawn shortly thereafter) in summer, and by days of total darkness in winter. The long harsh winters and lack of sunshine allow only mosses, lichens, and dwarf willows and shrubs to sprout low above the barren permafrost (see Glossary). Although the great Siberian rivers slowly traverse this zone in reaching the Arctic Ocean, drainage of the numerous lakes, ponds, and swamps is hampered by partial and intermittent thawing. Frost weathering is the most important physical process here, shaping a landscape modified by extensive glaciation in the last Ice Age. Less than 1 percent of the Soviet population lives in this zone. The fishing and port industries of the Kola Peninsula and the huge oil and gas fields of northwestern Siberia are the largest employers in the tundra. The frontier city of Noril'sk, for example, with a population of 181,000 in 1987, is one of the largest settlements above the Arctic Circle.

The northern forests of spruce, fir, cedar, and larch, collectively known as the taiga, make up the largest natural zone of the Soviet Union, an area about the size of the United States. Here too the winter is long and severe, as witnessed by the routine registering of the world's coldest temperatures for inhabited areas in the northeastern portion of this belt. The taiga zone extends in a broad band across the middle latitudes, stretching from the Finnish border in the west to the Verkhoyansk Range in northeastern Siberia and as far south as the southern shores of Lake Baykal. Isolated sections of taiga are found along mountain ranges, as in the southern part of the Urals, and in the Amur River Valley in the Far East. About 33 percent of the population lives in this zone, which, with the mixed forest zone, includes most of the European part of the Soviet Union and the ancestral lands of the earliest Slavic settlers.

Long associated with traditional images of Russian landscape and cossacks (see Glossary) on horseback are the steppes, which are treeless, grassy plains. Although they cover only 15 percent of Soviet territory, the steppes are home to roughly 44 percent of the population. They extend for 4,000 kilometers from the Carpathian Mountains in the western Ukrainian Republic across most of the northern portion of the Kazakh Republic in Soviet Central Asia, between the taiga and arid zones, occupying a relatively narrow band of plains whose chernozen (see Glossary) soils are some of the most fertile on earth. In a country of extremes, the steppe zone, with its moderate temperatures and normally adequate levels of sunshine and moisture, provides the most favorable conditions for human settlement and agriculture. Even here, however, agricultural yields are sometimes adversely affected by unpredictable levels of precipitation and occasional catastrophic droughts (see Production , ch. 13).

Below the steppes, and merging at times with them, is the arid zone: the semideserts and deserts of Soviet Central Asia and, particularly, of the Kazakh Republic. Portions of this zone have become cotton- and rice-producing regions through intensive irrigation. For various reasons, including sparse settlement and a comparatively mild climate, the arid zone has become the most prominent center for Soviet space exploration.

One-quarter of the Soviet Union consists of mountains or mountainous terrain. With the significant exceptions of the Ural Mountains and the mountains of eastern Siberia, the mountains occupy the southern periphery of the Soviet Union. The Urals, because they have traditionally been considered the natural boundary between Europe and Asia and because they are valuable sources of minerals, are the most famous of the country's nine major ranges. In terms of elevation (comparable to the Appalachians) and vegetation, however, they are far from impressive, and they do not serve as a formidable natural barrier.

Truly alpine terrain is found in the southern mountain ranges. Between the Black and Caspian seas, for example, the Caucasus Mountains rise to impressive heights, marking a continuation of the boundary separating Europe from Asia. One of the peaks, Mount El'brus, is the highest point in Europe at 5,642 meters. This range, extending to the northwest as the Crimean and Carpathian mountains and to the southeast as the Tien Shan and Pamirs, forms an imposing natural barrier between the Soviet Union and its neighbors to the south. The highest point in the Soviet Union, at 7,495 meters, is Mount Communism (Pik Kommunizma) in the Pamirs near the border with Afghanistan, Pakistan, and China. The Pamirs and the Tien Shan are offshoots of the tallest mountain chain in the world, the Himalayas. Eastern Siberia and the Soviet Far East are also mountainous regions, especially the volcanic peaks of the long Kamchatka Peninsula, which juts down into the Sea of Okhotsk. The Soviet Far East, the southern portion of Soviet Central Asia, and the Caucasus are the Soviet Union's centers of seismic activity. In 1887, for example, a severe earthquake destroyed the city of Vernyy (present-day Alma-Ata), and in December 1988 a massive quake demolished the Armenian city of Spitak and large sections of Kirovakan and Leninakan. The 1988 quake, one of the worst in Soviet history, claimed more than 25,000 lives.

The Soviet Union's water resources are both scarce and abundant. With about 3 million rivers and approximately 4 million inland bodies of water, the Soviet Union holds the largest fresh, surface-water resources of any country. Unfortunately, most of these resources (84 percent), as with so much of the Soviet resource base, are at a great distance from consumers; they flow through sparsely populated territory and into the Arctic and Pacific oceans. In contrast, areas with the highest concentrations of population, and therefore the highest demand for water supplies, tend to have the warmest climates and highest rates of evaporation. The result is barely adequate (or in some cases inadequate) water resources where they are needed most.

Nonetheless, as in many other countries, the earliest settlements sprang up on the rivers, and that is where the majority of the urban population prefers to live. The Volga, Europe's longest river, is by far the Soviet Union's most important commercial waterway. Three of the country's twenty-three cities with more than 1 million inhabitants are located on its banks: Gor'kiy, Kazan', and Kuybyshev.

The European part of the Soviet Union has extensive, highly developed, and heavily used water resources, among them the key hydrosystems of the Volga, Kama, Dnepr, Dnestr, and Don rivers. As is the case with fuels, however, the greatest water resources are found east of the Urals, deep in Siberia. Of the sixty-three rivers in the Soviet Union longer than 1,000 kilometers, forty are east of the Urals, including the four mighty rivers that drain Siberia as they flow northward to the Arctic Ocean: the Irtysh, Ob', Yenisey, and Lena rivers. The Amur River forms part of the winding and sometimes tense boundary between the Soviet Union and China. Taming and exploiting the hydroelectric potential of these systems has been a monumental and highly publicized national project. Some of the world's largest hydroelectric stations operate on these rivers. Hundreds of smaller hydroelectric power plants and associated reservoirs have also been constructed on the rivers. Thousands of kilometers of canals link river and lake systems and provide essential sources of irrigation for farmland.

The Soviet Union's 4 million inland bodies of water are chiefly a legacy of extensive glaciation. Most prominent among them are the Caspian Sea, the world's largest inland sea, and Lake Baykal, the world's deepest and most capacious freshwater lake. Lake Baykal alone holds 85 percent of the freshwater resources of the lakes in the Soviet Union and 20 percent of the world's total. Other water resources include swampland, a sizable portion of territory (10 percent), and glaciers in the northern areas.

Data as of May 1989

NOTE: The information regarding Soviet Union (former) on this page is re-published from The Library of Congress Country Studies and the CIA World Factbook. No claims are made regarding the accuracy of Soviet Union (former) Topography and Drainage information contained here. All suggestions for corrections of any errors about Soviet Union (former) Topography and Drainage should be addressed to the Library of Congress and the CIA.