WEST SIBERIAN PLAIN, West Siberian Lowland, one of the largest plains globe (the third largest after the Amazon and East European plains), in northern Asia, Russia and Kazakhstan. Occupies the entire Western Siberia, stretching from the coast of the Arctic Ocean in the north to the Turgai plateau and the Kazakh small hills in the south, from the Urals in the west to the Central Siberian Plateau in the east. The length from north to south is up to 2500 km, from west to east from 900 km in the north to 2000 km in the south. The area is about 3 million km 2, including 2.6 million km 2 in Russia. The prevailing heights do not exceed 150 m. The lowest parts of the plain (50–100 m) are located mainly in the central (Kondinskaya and Sredneobskaya lowlands) and northern (Lower Obskaya, Nadymskaya and Purskaya lowlands) parts. The highest point of the West Siberian Plain - up to 317 m - is located on the Ob Plateau.
At the base of the West Siberian Plain lies West Siberian Platform. In the east it borders Siberian platform, in the south – with Paleozoic structures Central Kazakhstan, Altai-Sayan region, in the west - with the folded system of the Urals.
Relief
The surface is a low accumulative plain with a fairly uniform topography (more uniform than the relief of the East European Plain), the main elements of which are wide flat interfluves and river valleys; characteristic various shapes manifestations of permafrost (extended up to 59 ° N latitude), increased swampiness and developed (mainly in the south in loose rocks and soils) ancient and modern salt accumulation. In the north, in the area of distribution of marine accumulative and moraine plains (Nadym and Pur lowlands), the general flatness of the territory is broken by moraine gently ridged and hilly-ridged (North-Sosvinskaya, Lyulimvor, Verkhne-, Srednetazovskaya, etc.) hills with a height of 200–300 m, whose southern border runs around 61–62°N. sh.; they are covered in a horseshoe shape from the south by flat-topped hills, including the Poluyskaya Upland, Belogorsky Continent, Tobolsk Continent, Sibirskie Uvaly (245 m), etc. In the north, permafrost exogenous processes(thermoerosion, soil heaving, solifluction), deflation is common on sandy surfaces, and peat accumulation is common in swamps. On the Yamal, Tazovsky and Gydansky peninsulas, permafrost is widespread; The thickness of the frozen layer is very significant (up to 300–600 m).
To the south, the area of moraine relief is adjacent to flat lacustrine and lacustrine-alluvial lowlands, the lowest (40–80 m high) and the most swampy of which are the Kondinskaya lowland and the Middle Ob lowland with the Surgut lowland (height 105 m). This territory, not covered by Quaternary glaciation (south of the Ivdel-Ishim-Novosibirsk-Tomsk-Krasnoyarsk line), is a weakly dissected denudation plain, rising to 250 m to the west, to the foot of the Urals. In the area between the Tobol and Irtysh rivers there is a sloping, in some places with ragged ridges, lacustrine-alluvial Ishim Plain(120–220 m) with a thin cover of loess-like loams and loess overlying salt-bearing clays. Adjacent to it are alluvial Baraba Lowland, Vasyugan Plain and Kulunda Plain, where the processes of deflation and modern salt accumulation are developed. In the foothills of Altai there are the Priob Plateau and the Chulym Plain.
For geological structure and mineral resources, see Art. West Siberian Platform ,
Climate
The West Siberian Plain is dominated by a harsh, continental climate. The significant extent of the territory from north to south determines the well-defined latitudinal climate zonation and noticeable differences climatic conditions northern and southern parts of the plain. The nature of the climate is significantly influenced by the Arctic Ocean, as well as the flat terrain, which facilitates the unhindered exchange of air masses between north and south. Winter in polar latitudes is severe and lasts up to 8 months (the polar night lasts almost 3 months); average temperature January from –23 to –30 °C. In the central part of the plain, winter lasts almost 7 months; The average temperature in January is from –20 to –22 °C. In the southern part of the plain, where the influence of the Asian anticyclone increases, at the same average monthly temperatures, winter is shorter - 5–6 months. The minimum air temperature is –56 °C. The duration of snow cover in the northern regions reaches 240–270 days, and in the southern regions – 160–170 days. The thickness of the snow cover in the tundra and steppe zones is 20–40 cm, in the forest zone – from 50–60 cm in the west to 70–100 cm in the east. In summer, the westerly transport of Atlantic air masses predominates with invasions of cold Arctic air in the north, and dry warm air masses from Kazakhstan and Central Asia in the south. In the north of the plain, summer, which begins under polar day conditions, is short, cool and humid; in the central part it is moderately warm and humid, in the south it is arid and dry with hot winds and dust storms. The average July temperature increases from 5 °C in the Far North to 21–22 °C in the south. The duration of the growing season in the south is 175–180 days. Atmospheric precipitation falls mainly in summer (from May to October - up to 80% of precipitation). The most precipitation - up to 600 mm per year - falls in the forest zone; the wettest ones are the Kondinskaya and Sredneobskaya lowlands. To the north and south, in the tundra and steppe zones, the annual precipitation gradually decreases to 250 mm.
Surface water
More than 2,000 rivers flowing through the West Siberian Plain belong to the Arctic Ocean basin. Their total flow is about 1200 km 3 of water per year; up to 80% of the annual runoff occurs in spring and summer. The largest rivers - the Ob, Yenisei, Irtysh, Taz and their tributaries - flow in well-developed deep (up to 50–80 m) valleys with a steep right bank and a system of low terraces on the left bank. The rivers are fed by mixed water (snow and rain), the spring flood is extended, and the low water period is long in summer, autumn and winter. All rivers are characterized by slight slopes and low flow speeds. Ice cover on rivers lasts up to 8 months in the north, and up to 5 months in the south. Large rivers are navigable, are important rafting and transport routes and, in addition, have large reserves of hydropower resources.
There are about 1 million lakes on the West Siberian Plain, total area of which there are more than 100 thousand km 2. The largest lakes are Chany, Ubinskoye, Kulundinskoye, etc. Lakes of thermokarst and moraine-glacial origin are common in the north. In the suffusion depressions there are many small lakes (less than 1 km2): in the interfluve of the Tobol and Irtysh - more than 1500, in the Barabinskaya Lowland - 2500, among them many are fresh, salty and bitter-salty; There are self-sedating lakes. The West Siberian Plain is distinguished by a record number of swamps per unit area (the area of the wetland is about 800 thousand km 2).
Types of landscapes
The uniformity of the relief of the vast West Siberian Plain determines a clearly defined latitudinal zonation of landscapes, although in comparison with the East European Plain natural areas here they are shifted to the north; landscape differences within the zones are less noticeable than on the East European Plain, and there is no zone of broad-leaved forests. Due to the poor drainage of the territory, hydromorphic complexes play a prominent role: swamps and swampy forests occupy about 128 million hectares here, and in the steppe and forest-steppe zones there are many solonetzes, solods and solonchaks.
On the Yamal, Tazovsky and Gydansky peninsulas, in conditions of continuous permafrost, landscapes of arctic and subarctic tundra with moss, lichen and shrub ( dwarf birch, willow, alder) vegetation on gley soils, peat gley soils, peat podburs and turf soils. Polygonal grass-hypnum bogs are widespread. The share of indigenous landscapes is extremely small. To the south, tundra landscapes and swamps (mostly flat-hilly) are combined with larch and spruce-larch woodlands on podzolic-gley and peat-podzolic-gley soils, forming a narrow forest-tundra zone, transitional to the forest (forest-swamp) zone temperate zone, represented by the subzones of northern, middle and southern taiga. What is common to all subzones is swampiness: over 50% of the northern taiga, about 70% - middle, about 50% - southern. The northern taiga is characterized by flat- and large-hilly raised bogs, the middle one - ridge-hollow and ridge-lake bogs, the southern one - hollow-ridge, pine-shrub-sphagnum, transitional sedge-sphagnum and lowland tree-sedge. The largest swamp massif - Vasyugan Plain. Forest complexes of different subzones are unique, formed on slopes with varying degrees of drainage.
Northern taiga forests on permafrost are represented by sparse, low-growing, heavily swampy, pine, pine-spruce and spruce-fir forests on gley-podzolic and podzolic-gley soils. Indigenous landscapes of the northern taiga occupy 11% of the plain's area. Indigenous landscapes in the middle taiga occupy 6% of the area of the West Siberian Plain, in the southern - 4%. What is common to the forest landscapes of the middle and southern taiga is the wide distribution of lichen and dwarf-sphagnum pine forests on sandy and sandy loam ferruginous and illuvial-humus podzols. On loam soils in the middle taiga, along with extensive swamps, there are spruce-cedar forests with larch and birch forests on podzolic, podzolic-gley, peat-podzolic-gley and gley peat-podzols.
In the subzone of the southern taiga on loams - spruce-fir and fir-cedar (including urmans - dense dark coniferous forests with a predominance of fir), small grass forests and birch forests with aspen on sod-podzolic and sod-podzolic-gley (including with a second humus horizon) and peat-podzolic-gley soils.
The subtaiga zone is represented by parkland pine, birch and birch-aspen forests on gray, gray gley and soddy-podzolic soils (including with a second humus horizon) in combination with steppe meadows on cryptogleyed chernozems, sometimes solonetzic. Indigenous forest and meadow landscapes have practically not been preserved. Swampy forests turn into lowland sedge-hypnum (with ryams) and sedge-reed bogs (about 40% of the zone's territory). For forest-steppe landscapes of sloping plains with loess-like and loess covers on salt-bearing tertiary clays, birch and aspen-birch groves on gray soils and malts in combination with forb-grass steppe meadows on leached and cryptogleyed chernozems are typical, to the south - with meadow steppes on ordinary chernozems, places mi solonetzic and solonchakous. There are pine forests on the sands. Up to 20% of the zone is occupied by eutrophic reed-sedge bogs. In the steppe zone, indigenous landscapes have not been preserved; in the past these were forb-feather grass steppe meadows on ordinary and southern chernozems, saline in places, and in drier ones southern regions– fescue-feather grass steppes on chestnut and cryptogley soils, gley solonetzes and solonchaks.
Environmental problems and protected natural areas
In oil production areas, due to pipeline breaks, water and soil are polluted with oil and petroleum products. In forestry areas there are overcuttings, waterlogging, the spread of silkworms, and fires. In agricultural landscapes there is an acute problem of lack of fresh water, secondary salinization of soils, destruction of soil structure and loss of soil fertility during plowing, drought and dust storms. In the north, there is degradation of reindeer pastures, in particular due to overgrazing, which leads to a sharp reduction in their biodiversity. No less important is the problem of preserving hunting grounds and natural habitats of fauna.
Numerous reserves, national and natural parks have been created to study and protect typical and rare natural landscapes. Among the largest reserves: in the tundra - Gydansky Reserve, in the northern taiga - Verkhnetazovsky Reserve, in the middle taiga - Yugansky Reserve and Malaya Sosva, etc. In the sub-taiga it was created national park Pripyshminskie Bors. Natural parks have also been organized: in the tundra - Oleniy Ruchi, in the north. taiga - Numto, Siberian Uvaly, in the middle taiga - Kondinsky lakes, in the forest-steppe - Bird Harbor.
The first acquaintance of Russians with Western Siberia probably took place back in the 11th century, when the Novgorodians visited the lower reaches of the Ob River. With the campaign of Ermak (1582–85), a period of discoveries in Siberia and the development of its territory began.
The West Siberian Plain is not only one of the largest objects of its kind on the globe. It is the most developed and populated part of Siberia. Its borders are marked by the steppes of Kazakhstan, the shores of the Kara Sea, the Urals and the Central Siberian Plateau. The first characteristics of the West Siberian Plain were formed after Ermak’s campaign and his conquest of the region. But serious study was carried out much later.
Speaking the language of numbers
The shape of the plain resembles a trapezoid with a narrow side in the north. Its width ranges from 800 to 1900 km, its length is about 2500 km. The total area of the area is almost three million square kilometers. The plain has a slope coming from the south. But its entire territory is distinguished by an exceptionally flat surface without large differences in altitude (up to one hundred meters above sea level). Only near the borders (except for the northern part) there are hills reaching up to 300 m.
Composition of the plain
To give full description West Siberian Plain, it is necessary to describe its components separately. The entire territory is divided into several parts. This:
- The Ishim Plain, located between the Irtysh and Tobol rivers. This is a flat area, indented by basins, hollows, and ridges. It has a large number of lakes (fresh, salty, bitter-salty). The soil is suitable for farming, so almost the entire plain is plowed.
- The Kulunda Plain is located between the Irtysh and Ob. It is distinguished by the presence of high ridges, depressions filled with rivers, drainless lakes and deposits of salt and soda. Much of the plain is used for agriculture.
- The Baraba Lowland is an undulating plain dominated by birch forests, swamps, salt marshes and meadows. Part of it is plowed, land reclamation is being carried out, and the area specializes in agriculture and dairy farming.
- The Vasyugan Plain is a heavily swampy area between the Ob and Irtysh. Here is the largest swamp in the world (Vasyuganskoye), and many rivers. Rich deposits of oil, gas, peat and iron ore have been discovered.
- Siberian Uvaly is a chain of hills that stretches from the Ob from west to east to the Yenisei. The area is covered with coniferous and small-leaved trees (taiga).
- The Irtysh Plain stretches for 800 km along the Irtysh. Used for agricultural work (farming and dairy farming) in Russia and Kazakhstan.
Other terrain features
The characteristics of the West Siberian Plain will be incomplete without mentioning the climate, rivers, flora and fauna. There is a very harsh continental climate here. In the southern part, droughts are common; snow cover lasts up to six months. The region is rich in underground water; there are many rivers on the surface. The largest of them are the Ob, Yenisei and Irtysh, which are characterized by a slow and calm current. They contain bream and carp. Trees on the plain include birch, linden, pine, cedar, and aspen. The fauna is represented by almost five hundred species, among which the most common are: hamster, chipmunk, mink, and teledut squirrel.
1) Using maps from a textbook or atlas, determine which large natural areas Western Siberia borders on and what surface forms predominate here.
Western Siberia borders the Urals, Central Siberia, Southern Siberia
2) Which federal subjects are part of this natural region.
Yamalo-Nenets Automobile District, Khanty-Mansiysk autonomous region, Krasnoyarsk region, Tyumen region, Omsk region, Tomsk region, Novosibirsk region.
Questions in a paragraph
*Use the textbook map to determine which geometric figure resemble the outlines of the West Siberian Plain. In which part of the plain is the extent from west to east the smallest, and in which is the greatest?
The plain has the shape of a trapezoid.
*Based on the drawing, tell us about the main stages of development of the territory of the West Siberian Plain.
The basis of the plain is an ancient Paleozoic platform. The foundation is covered by a thick cover of Mesozoic and Cenozoic marine and continental predominantly sandy-clayey sediments.
*Use the maps of the textbook and atlas to determine how much solar radiation the northern, middle and southern parts of the West Siberian Plain receive, what average temperatures in January and July are typical for these territories.
Average annual temperatures range from -10.5°C in the north to 1-2°C in the south, average January temperatures from -28 to -16°C, July from 4 to 22°C.
Solar radiation is distributed as follows: north - 800 MJ/m2, middle zone - 1600, south - about 2000 MJ/m2.
*How is precipitation distributed on the West Siberian Plain? Explain why.
The distribution of precipitation over the territory is zonal. Largest quantity their (550 - 650 mm) falls in a strip stretching from the Urals to the Yenisei through the middle reaches of the Ob (forest zone). Within this strip, there is a slight increase in precipitation to the east, due to the barrier role of the Central Siberian Plateau and an increase in air humidity when passing over the swampy surface of the plain.
To the north and south of the strip of heaviest precipitation, their amount gradually decreases to 350 mm. To the north this is due to an increase in the frequency of arctic air with low moisture content, and to the south due to a weakening of cyclonic activity and rising temperatures.
Questions at the end of the paragraph
2. Compare the geographical location of the West Siberian and Russian plains and determine their similarities and differences.
The West Siberian and Russian plains are located on the Eurasian continent, located at high latitudes, have large areas. The Russian Plain occupies the European part. Among all the plains of our Motherland, only it opens to two oceans. Russia is located in the central and eastern parts of the plain. It stretches from the coast Baltic Sea before Ural mountains, from the Barents and White Seas to the Azov and Caspian Seas. The West Siberian Plain is a plain in northern Asia, occupies the entire western part Siberia from the Ural Mountains in the west to the Central Siberian Plateau in the east. In the north it is limited by the coast of the Kara Sea, in the south it extends to the Kazakh small hills, in the southeast the West Siberian Plain.
3. What is the reason for the unique relief of the West Siberian Plain?
Nowhere in the world can one find such a huge space with such a flat topography, seemingly sloping towards its center. This relief was formed by loose river sediments and ancient glacial sediments, which covered the Paleozoic plate with a thick sedimentary cover (3-4 thousand m). Horizontal layering of sedimentary layers - main reason flat terrain of the plain.
4. Explain the reason for the severe swampiness of the plain?
There are several reasons for the formation of such vast wetlands: the presence of excess moisture, flat terrain, permafrost, low air temperatures, the ability of peat, which predominates here, to retain water in quantities many times greater than the weight of the peat mass.
IOWest Siberian Plain- the plain is located in northern Asia, occupies the entire western part of Siberia from the Ural Mountains in the west to the Central Siberian Plateau in the east. In the north it is limited by the coast of the Kara Sea, in the south it extends to the Kazakh small hills, in the southeast the West Siberian Plain, gradually rising, gives way to the foothills of Altai, Salair, Kuznetsk Altai and Mountain Shoria. The plain has the shape of a trapezoid tapering towards the north: the distance from its southern border to the northern reaches almost 2500 km, the width is from 800 to 1900 km, and the area is only slightly less than 3 million km².
The West Siberian Plain is the most populated and developed (especially in the south) part of Siberia. Within its borders are the Tyumen, Kurgan, Omsk, Novosibirsk and Tomsk regions, Yamalo-Nenets and Khanty-Mansiysk autonomous okrugs, eastern regions of the Sverdlovsk and Chelyabinsk regions, a significant part of the Altai Territory, western regions of the Krasnoyarsk Territory (about 1/7 of the area of Russia). In the Kazakh part, within its boundaries there are areas of the North Kazakhstan, Akmola, [[Pavlodar region|Pavlodar], Kustanai and East Kazakhstan regions of Kazakhstan.
Relief and geological structure
The surface of the West Siberian Lowland is flat with a fairly insignificant difference in elevation. However, the relief of the plain is quite diverse. The lowest areas of the plain (50-100 m) are located mainly in the central (Kondinskaya and Sredneobskaya lowlands) and northern (Nizhneobskaya, Nadymskaya and Purskaya lowlands) parts. Along the western, southern and eastern outskirts stretch low (up to 200-250 m) hills: North Sosvinskaya and Turinskaya, Ishim Plain, Priobskoye and Chulym-Yenisei Plateau, Ket-Tymskaya, Verkhnetazovskaya and Lower Yenisei uplands. A clearly defined strip of hills is formed in the inner part of the Sibirskie Uvaly plain ( average height- 140-150 m), stretching from the west from the Ob to the east to the Yenisei, and the Vasyugan Plain parallel to them.
The relief of the plain is largely determined by its geological structure. At the base of the West Siberian Plain lies the epi-Hercynian West Siberian Plate, the foundation of which is composed of intensely dislocated Paleozoic sediments. The formation of the West Siberian plate began in the Upper Jurassic, when, as a result of breaking off, destruction and degeneration, a huge area between the Urals and the Siberian platform subsided, and a huge sedimentation basin arose. During its development, the West Siberian Plate was repeatedly captured by marine transgressions. At the end of the Lower Oligocene, the sea left the West Siberian plate, and it turned into a huge lacustrine-alluvial plain. In the middle and late Oligocene and Neogene, the northern part of the plate experienced uplift, which gave way to subsidence in Quaternary time. General move The development of the plate with the subsidence of colossal spaces resembles an incomplete process of oceanization. This feature of the slab is emphasized by the phenomenal development of wetlands.
Individual geological structures, despite the thick layer of sediments, are reflected in the relief of the plain: for example, the Verkhnetazovskaya and Lyulimvor hills correspond to gentle anticlinal uplifts, and the Barabinskaya and Kondinskaya lowlands are confined to the syneclises of the foundation of the plate. However, in Western Siberia, discordant (inversion) morphostructures are also common. These include, for example, the Vasyugan Plain, formed on the site of a gently sloping syneclise, and the Chulym-Yenisei Plateau, located in the zone of basement deflection.
Horizons are enclosed in a collar of loose sediments groundwater- fresh and mineralized (including brine), there are also hot (up to 100-150°C) waters. There are industrial deposits of oil and natural gas (West Siberian oil and gas basin). In the area of the Khanty-Mansi syneclise, Krasnoselsky, Salym and Surgut regions, in the layers of the Bazhenov formation at a depth of 2 km, there are the largest shale oil reserves in Russia.
Video on the topic
Climate
West Siberian Plain. Flood of the Taz and Ob rivers. July, 2002
The West Siberian Plain is characterized by a harsh, fairly continental climate. Its large extent from north to south determines a clearly defined climate zonation and significant differences in climatic conditions in the northern and southern parts of Western Siberia. The continental climate of Western Siberia is also significantly influenced by the proximity of the Arctic Ocean. The flat terrain facilitates the exchange of air masses between its northern and southern regions.
During the cold period, within the plain there is an interaction between an area of relatively high atmospheric pressure, located above southern part plains, and an area of low pressure, which in the first half of winter stretches in the form of a trough of the Icelandic pressure minimum over the Kara Sea and the northern peninsulas. In winter, continental air masses of temperate latitudes predominate, which come from Eastern Siberia or are formed locally as a result of cooling of the air over the plain.
Cyclones often pass through the border zone of areas of high and low pressure. Therefore, in winter the weather in the coastal provinces is very unstable; on the coast of Yamal and the Gydan Peninsula occur strong winds, the speed of which reaches 35-40 m/sec. The temperature here is even slightly higher than in neighboring forest-tundra provinces, located between 66 and 69° N. w. However, further south, winter temperatures gradually rise again. In general, winter is characterized by stable low temperatures, there are few thaws. Minimum temperatures throughout Western Siberia they are almost the same. Even near the southern border of the country, in Barnaul, there are frosts down to −50…−52°. Spring is short, dry and relatively cold; April, even in the forest-swamp zone, is not yet quite a spring month.
In the warm season, low pressure is established over Western Siberia, and an area of higher pressure forms over the Arctic Ocean. high pressure. In connection with this summer, weak northern or northeastern winds predominate and the role of westerly air transport noticeably increases. In May there is a rapid increase in temperatures, but often, when arctic air masses invade, there are returns of cold weather and frosts. The warmest month is July, the average temperature of which is from 3.6° on Bely Island to 21-22° in the Pavlodar area. The absolute maximum temperature is from 21° in the north (Bely Island) to 44° in the extreme southern regions (Rubtsovsk). High summer temperatures in the southern half of Western Siberia are explained by the arrival of heated continental air from the south - from Kazakhstan and Central Asia. Autumn comes late.
The duration of snow cover in the northern regions reaches 240-270 days, and in the south - 160-170 days. The thickness of the snow cover in the tundra and steppe zones in February is 20-40 cm, in the forest-swamp zone - from 50-60 cm in the west to 70-100 cm in the eastern Yenisei regions.
Harsh climate northern regions Western Siberia contributes to soil freezing and widespread permafrost. On the Yamal, Tazovsky and Gydansky peninsulas, permafrost is found everywhere. In these areas of continuous (merged) distribution, the thickness of the frozen layer is very significant (up to 300-600 m), and its temperatures are low (in watershed areas - 4. -9°, in valleys -2. -8°). To the south, within the northern taiga to a latitude of approximately 64°, permafrost occurs in the form of isolated islands interspersed with taliks. Its power decreases, temperatures rise to 0.5–1°, and the depth of summer thawing also increases, especially in areas composed of mineral rocks.
Hydrography
The territory of the plain is located within the large West Siberian artesian basin, in which hydrogeologists distinguish several second-order basins: Tobolsk, Irtysh, Kulunda-Barnaul, Chulym, Ob, etc. Due to the large thickness of the cover of loose sediments, consisting of alternating water-permeable (sands) , sandstones) and water-resistant rocks, artesian basins are characterized by a significant number of aquifers confined to formations of various ages - Jurassic, Cretaceous, Paleogene and Quaternary. The quality of groundwater in these horizons is very different. In most cases, artesian waters of deep horizons are more mineralized than those lying closer to the surface.
More than 2,000 rivers flow on the territory of the West Siberian Plain, the total length of which exceeds 250 thousand km. These rivers carry about 1,200 km³ of water into the Kara Sea annually - 5 times more than the Volga. The density of the river network is not very large and varies depending on the different places depending on the relief and climatic features: in the Tavda basin it reaches 350 km, and in the Barabinsk forest-steppe - only 29 km per 1000 km². Some southern regions of the country with a total area of more than 445 thousand km² belong to areas of closed drainage and are distinguished by an abundance of drainless lakes.
The main sources of nutrition for most rivers are melted snow waters and summer-autumn rains. In accordance with the nature of the food sources, the runoff is uneven over the seasons: approximately 70-80% of its annual amount occurs in spring and summer. Especially a lot of water flows down during the spring flood, when the level of large rivers rises by 7-12 m (in the lower reaches of the Yenisei even up to 15-18 m). For a long time (in the south - five, and in the north - eight months), Western Siberian rivers are frozen. Therefore on winter months accounts for no more than 10% of the annual runoff.
The rivers of Western Siberia, including the largest ones - the Ob, Irtysh and Yenisei, are characterized by slight slopes and low flow speeds. For example, the fall of the Ob riverbed in the area from Novosibirsk to the mouth over a distance of 3000 km is only 90 m, and its flow speed does not exceed 0.5 m/sec.
On the West Siberian Plain there are about one million lakes, the total area of which is more than 100 thousand km². Based on the origin of the basins, they are divided into several groups: those occupying the primary unevenness of the flat terrain; thermokarst; moraine-glacial; lakes of river valleys, which in turn are divided into floodplain and oxbow lakes. Peculiar lakes - “fogs” - are found in the Ural part of the plain. They are located in wide valleys, overflow in the spring, sharply reducing their size in the summer, and by autumn many disappear altogether. In the southern regions, lakes are often filled with salt water. The West Siberian Lowland holds the world record for the number of swamps per unit area (the area of the wetland is about 800 thousand square kilometers). The reasons for this phenomenon are the following factors: excess moisture, flat topography, permafrost and the ability of the peat available here to large quantities, hold a significant mass of water.
Natural areas
The large extent from north to south contributes to a pronounced latitudinal zonality in the distribution of soils and vegetation cover. Within the country there are gradually replacing one another tundra, forest-tundra, forest-swamp, forest-steppe, steppe and semi-desert (in the extreme south) zones. In all zones, lakes and swamps occupy fairly large areas. Typical zonal landscapes are located on dissected and better drained upland and riverine areas. In poorly drained interfluve spaces, where drainage is difficult and the soils are usually very wet, swamp landscapes predominate in the northern provinces, and landscapes formed under the influence of saline groundwater in the south
The West Siberian Plain is one of the largest accumulative lowland plains on the globe. It extends from the shores of the Kara Sea to the steppes of Kazakhstan and from the Urals in the west to the Central Siberian Plateau in the east. The comparative uniformity of the relief (Fig. 3) determines the clearly defined zoning of the landscapes of Western Siberia - from tundra in the north to steppe in the south (Fig. 4). Due to the poor drainage of the territory within its boundaries, hydromorphic complexes play a very prominent role: swamps and swampy forests occupy a total of about 128 million hectares, and in the steppe and forest-steppe zones there are many solonetzes, solods and solonchaks. The plain has the shape of a trapezoid tapering to the north: the distance from its southern border to the northern reaches almost 2500 km, the width is from 800 to 1900 km, and the area is only slightly less than 3 million km 2.
Geographical position The West Siberian Plain determines the transitional nature of its climate between the moderate continental climate of the Russian Plain and the sharply continental climate Central Siberia. Therefore, the country’s landscapes are distinguished by a number of unique features: the natural zones here are somewhat shifted to the north compared to the Russian Plain, there is no zone of broad-leaved forests, and landscape differences within the zones are less noticeable than on the Russian Plain. The West Siberian Plain is the most populated and developed (especially in the south) part of Siberia. Within its boundaries are Tyumen, Kurgan, Omsk, Novosibirsk, Tomsk, a significant part Altai Territory, as well as some eastern regions of the Sverdlovsk and Chelyabinsk regions and western regions of the Krasnoyarsk Territory.
Rice. 3
Rice. 4
Provinces: 1 - Yamailskaya; 2 - Tazovskaya; 3 - Gydanskaya; 4 - Obsko-Tazovskaya; 5 - Yeniseisko-Tazovskaya; 6 - Severososvinskaya; 7 - Ob-Purskaya; 8 - Prieniseiskaya: 9 - Poduralskaya; 10 - Sredneobskaya; 11 - Vasyuganskaya; 12 - Chulym-Yenisei; 13 - Nezhneobskaya; 14 - Trans-Ural; 15 - Priishimskaya; 16 - Barabinskaya; 17 - Verkhneobskaya; 18 - Priturgayskaya; 19 - Priirtyshskaya; 20 - Kulundiyskaya.
The first acquaintance of Russians with Western Siberia probably took place in the 11th century, when the Novgorodians visited the lower reaches of the Ob. The campaign of Ermak (1581-1584) opens the brilliant period of the Great Russians geographical discoveries in Siberia and the development of its territory. However, scientific study of the country’s nature began only in the 18th century, when detachments of first the Great Northern and then academic expeditions were sent here. In the 19th century Russian scientists and engineers are studying the conditions of navigation on the Ob, Yenisei and the Kara Sea, the geological and geographical features of the route of the then designed Siberian railway, salt deposits in the steppe zone. A significant contribution to the knowledge of the Western Siberian taiga and steppes was made by the research of soil-botanical expeditions of the Resettlement Administration, undertaken in 1908-1914. in order to study the conditions of agricultural development of areas allocated for the resettlement of peasants from European Russia.
The study of the nature and natural resources of Western Siberia acquired a completely different scope after the Great October revolution. In the research that was necessary for the development of productive forces, it was no longer individual specialists or small detachments that took part, but hundreds of large complex expeditions and many scientific institutes created in various cities of Western Siberia. Detailed and comprehensive studies were carried out here by the USSR Academy of Sciences (Kulundinskaya, Barabinskaya, Gydanskaya and other expeditions) and its Siberian branch, the West Siberian Geological Department, geological institutes, expeditions of the Ministry Agriculture, Hydroproject and other organizations. As a result of these studies, ideas about the country's topography changed significantly, detailed soil maps were compiled in many regions of Western Siberia, and measures were developed to rational use saline soils and the famous West Siberian chernozems. The forest typological studies of Siberian geobotanists and the study of peat bogs and tundra pastures were of great practical importance. But the work of geologists brought especially significant results. Deep drilling and special geophysical research have shown that in the depths of many regions of Western Siberia there are rich deposits natural gas, large reserves of iron ore, brown coal and many other minerals, which already serve as a solid basis for the development of industry in Western Siberia.