Read on Mobile Reading mode. Interesting facts about rivers

general characteristics rivers

As we know, a river is a permanent natural water flow, flowing in the depression of the relief developed by it. All rivers are divided into mountain and plain (according to the nature of the flow). The main characteristics of rivers are indicators such as: length of the river, slope and fall of the river, volume of annual river flow, type of river feeding, river flow speed.

Russia, due to the size of its territory and climate, has a large number of rivers. Scientists have calculated that more than $3 million rivers flow through the country. Their total length exceeds $10$ million km. The vast majority of rivers are typical lowland rivers.

Note 1

In terms of annual river flow, Russia is second only to Brazil.

Rivers are distributed very unevenly throughout the country. This is due to the characteristics of the climate and terrain. Let's look at these topics in more detail.

Rivers of the Arctic Ocean basin

The territory of the northern part of the East European Plain, Siberia and parts Far East has a surface slope to the north. Therefore, more than half of the country's territory belongs to the Arctic Ocean basin. The largest of them are the systems of the Ob, Yenisei, and Lena. In the European part of the country, the largest rivers in the Arctic Ocean basin are the Northern Dvina and Pechora. The Lena River is the longest river in Russia (without tributaries). Its length is $4400$ km. The Yenisei is the deepest river in the basin and one of the deepest rivers in the world. The Ob River has the largest basin in terms of area.

Note 2

And if we measure the length of the Ob with its tributary Irtysh, then this particular system will be the longest in Russia - $5410$ km.

The rivers of the European part of the basin have a slow, calm flow. These are typically lowland rivers. They are significantly shorter than the rivers of Siberia. Siberian rivers originate far in the south, in the mountains Southern Siberia(Altai, Sayan Mountains, Transbaikalia). In the upper reaches they often have the character of mountain rivers and have rapids. In the middle and lower reaches there are lowland rivers.

The feeding type of northern rivers is snow and rain. Flood occurs in the spring, when spring rains coincide with snowmelt. Northern rivers freeze in winter. Ice melting occurs from south to north. Therefore, when meltwater comes to the north, and there is still ice there, river floods occur over large areas.

Northern rivers are rich in fish. And the Northern Dvina and Pechora in the old days were famous for their soft pearl fishing. Unfortunately, due to deterioration ecological situation soft pearls are no longer mined.

Siberian rivers have large energetic resources, so a number of powerful hydroelectric power stations were built there.

Rivers of the Pacific Ocean

The Pacific Ocean basin occupies approximately a fifth of Russia's territory. The largest river in this basin is the Amur. The rivers of the Amur basin are fed by rain, associated with the monsoon climate of the Far Eastern coast. The Amur is one of the deepest rivers in the world. The rivers of the coast of the Okhotsk and Bering seas are short. They belong to snow-fed rivers. A number of hydroelectric power stations have been built on the rivers of the Amur system. The state border with China runs along the Amur, Ussuri, and Argun rivers.

Rivers of the Atlantic Ocean

The Atlantic Ocean basin is the smallest. It accounts for about $5$% of the country's area. The type of river feeding is mixed, with a predominance of rain. As a rule, rivers are full all year round. They flow into the Baltic Sea Western Dvina, Neman, Neva. The Dnieper, Don and Kuban carry their waters to the south, into the Black and Azov Seas. The water of these rivers is actively used in agriculture for irrigation. In ancient times, a legendary path ran along the river system of the East European Plain "from the Varangians to the Greeks."

Rivers of the internal drainage region (Aral-Caspian basin)

The Caspian Sea basin covers the interior of the East European Plain, Southern Urals, eastern part of the Caucasus. It is called endorheic, since the Caspian does not communicate with the World Ocean and is a sea-lake. The most famous rivers of this basin - Volga, Ural, Araks, Terek.

The Volga basin occupies approximately $34% of the area of ​​the East European Plain. When it flows into the Caspian Sea, the Volga forms a vast delta (about $80 branches). Today the Volga is actually a whole cascade of reservoirs.

The canal system made it possible to unite the navigable rivers of the East European Plain into a single transport system (Volga-Don Canal, White Sea-Baltic Canal).

Note 3

Rational use rivers is today one of the most important directions of the state’s environmental policy. Because it's wrong economic activity can lead to global irreversible changes in nature, to the disappearance of many rivers, especially the so-called “small rivers”.

Russia occupies a vast geographical area, and it is not surprising that numerous rivers stretch across its expanses, which played an important historical role in the settlement and development of new lands. Almost everything is located on rivers Largest cities countries.

In total, there are about 3 million rivers on the territory of the Russian Federation, and all of them are an important component of the life of many people, animals and plants. Rivers provide us with food, water, electricity, places for recreation, and also serve as transport routes connecting different settlements. It is an indispensable source of water for Agriculture and industry.

In this article you can get acquainted with the largest rivers of Russia, get them brief description and to look geographical location on the map of the country.

Rivers of the Russian Federation

Map of the largest rivers in Russia

The country's territory is divided into European and Asian parts. The dividing line is usually considered to be the Ural Mountains and the Caspian Sea. The rivers of the European part flow into the Arctic Ocean, the Baltic Sea, the Black Sea and the Caspian Sea. The rivers of the Asian part flow into the Arctic and Pacific oceans.

The largest rivers in European Russia are the Volga, Don, Kama, Oka and Northern Dvina, while some rivers originate in Russia but flow into other countries, such as the Dnieper and Western Dvina. The following large rivers flow through the Asian expanses of the country: Ob, Irtysh, Yenisei, Angara, Lena, Yana, Indigirka and Kolyma.

Of the five main drainage basins: Arctic, Pacific, Baltic, Black Sea and Caspian, the first, located in Siberia and including the northern part of the Russian Plain, is the most extensive. To a large extent, this basin is filled by the three largest rivers in Russia: the Ob (3650 km), which, together with its main tributary, the Irtysh River, forms a river system 5410 km long, the Yenisei (3487 km), and the Lena (4400 km). The sum of their drainage areas exceeds 8 million km², and the total water flow is about 50,000 m³/s.

Siberia's major rivers provide transport arteries inland to the Arctic Sea Route, although they are blocked by ice for long periods each year. The slight slope of the Ob River causes it to slowly meander through a huge floodplain. Due to the flow to the north, from the upper reaches to the lower boundaries of the thaw, extensive flooding occurs quite often, which leads to the development of huge swamps. The Vasyugan swamps on the Ob-Irtysh interfluve cover an area of ​​more than 50,000 km².

The rivers of the rest of Siberia (about 4.7 million km²) flow into the Pacific Ocean. In the north, where the watershed is close to the coast, numerous small, fast-flowing streams flow from the mountains, but most of southeastern Siberia is drained by the Amur River. For most of its length, the Amur forms the border separating Russia and China. The Ussuri, one of the tributaries of the Amur, forms another significant border line between the countries.

Three large drainage basins are located in European Russia south of the Arctic Basin. The Dnieper, only the upper reaches of which are in Russia, as well as the Don and Volga are the longest European river, originating in the north-west of the Valdai Hills and flowing into the Caspian Sea. Second only to the Siberian rivers, the Volga basin covers an area of ​​1,380,000 km². The rivers of the East European Plain have long served as important transport arteries; in fact, the Volga river system provides two-thirds of the entire Russian inland waterway traffic.

10 largest and longest rivers in Russia

Many mighty rivers flow through the territory of the Russian Federation, but the size of some of them is truly impressive. Below is a list and maps of the country's largest rivers, both by length and by drainage basin area.

Lena

The Lena River is one of the most long rivers planets. It originates near Lake Baikal in southern Russia and flows west, and then above Yakutsk it smoothly turns north, where it flows into the Laptev Sea (a basin of the Arctic Ocean). Near its mouth, the river forms a huge delta with an area of ​​32,000 km, which is the largest in the Arctic and the largest protected area wildlife in Russia.

The Lena Delta, which floods every spring, serves as an important area for nesting and migration of birds, and also supports rich fish populations. The river is home to 92 planktonic species, 57 benthos species and 38 fish species. Sturgeon, burbot, chum salmon, whitefish, nelma and albula are the most commercially important fish species.

Swans, dippers, geese, ducks, plovers, waders, snipe, phalaropes, terns, skuas, predator birds, sparrows and gulls are just some of the migratory birds that nest in the Lena's productive wetlands.

Ob

The Ob is the seventh longest river in the world, stretching over a distance of 3,650 kilometers in the Western Siberian region of the Russian Federation. This river, which is of great economic importance for Russia, arises at the confluence of the Biya and Katun rivers in Altai. It mainly passes through the country, although many of its tributaries originate in China, Mongolia and Kazakhstan. The Ob is connected to its largest tributary by the Irtysh River, about 69° east longitude. Flows into the Kara Sea of ​​the Arctic Ocean, forming Ob Bay. The river has a huge drainage area, which is about 2.99 million km².

The habitat surrounding the Ob consists of vast expanses of steppe and taiga flora in the upper and middle reaches of the river. Birches, pines, firs and cedars are some of the famous trees growing in these areas. Thickets of willow, rose hips and bird cherry also grow along the watercourse. The river basin is replete with aquatic flora and fauna, including more than 50 species of fish (sturgeon, carp, perch, nelma and peled, etc.) and about 150 species of birds. Minks, wolves, Siberian moles, otters, beavers, stoats and other local mammal species. In the lower reaches of the Ob, the Arctic tundra is characterized by snow-covered landscapes for most of the year. Polar bears, arctic foxes, polar owls and arctic hares represent this region.

Volga

The longest river in Europe, the Volga, which is often considered the national river of Russia, has a large basin covering almost two-thirds of European Russia. The Volga originates in the north-west of the Valdai Hills, and flows south over 3530 km, where it flows into the Caspian Sea. About 200 tributaries join the river along the entire route. Eleven of the country's major cities, including Moscow, are located along the Volga basin, which covers an area of ​​1.36 million km².

The climate in the river basin varies along its course from north to south. In the northern regions it predominates temperate climate with cold snowy winters and warm humid summers. The southern regions are characterized by cool winters and hot, dry summers. The Volga Delta is one of the richest habitats, which is home to 430 plant species, 127 fish species, 260 bird species and 850 aquatic species.

Yenisei

The mouth of the Yenisei River is located near the city of Kazyl, where it merges with the Little Yenisei River, which originates in Mongolia and flows north, where it drains a vast area of ​​Siberia before emptying into the Kara Sea (Arctic Ocean), a journey of 3,487 km. The Angara River, which flows from Lake Baikal, is one of the main tributaries of the upper Yenisei.

The waters of the Yenisei are home to about 55 species of local fish, including Siberian sturgeon, flounder, roach, northern pike, Siberian gudgeon, tench and sterlet. Most of the river basin surrounds, mainly consisting of the following rocks coniferous trees: fir, cedar, pine and larch. In some areas of the upper Yenisei there are also steppe pastures. In the north, boreal forests give way to arctic forests. Musk deer, elk, roe deer and Japanese mouse- some species of mammals living in taiga forests along the river. Also found are birds such as the Siberian blue robin, Siberian lentil, capercaillie and wood snipe. Ducks, geese and swans are found in the lower reaches in the summer.

Lower Tunguska

The Lower Tunguska is a right tributary of the Yenisei, flowing through Irkutsk region And Krasnoyarsk region Russia. Its length is 2989 km, and the basin area is 473 thousand km². The river extends near the watershed between the Yenisei and Lena river basins and flows north and then west across the Central Siberian Plateau.

In the upper reaches the river forms a wide valley with numerous shallows, but after turning to the west the valley narrows and numerous gorges and rapids appear. In the river basin lies the vast Tunguska coal basin.

Amur

The Amur is the tenth longest river in the world, located in East Asia and forms the border between Far Eastern District Russian Federation and Northeast China. The river originates at the confluence of the Shilka and Argun rivers. The Amur flows for 2825 km to the northwestern part of the Pacific Ocean and flows into the Sea of ​​Okhotsk.

The river has many vegetation zones in various parts of its basin, including taiga forests and swamps, Manchurian mixed forests, Amur meadow steppes, forest-steppes, steppes and tundra. The wetlands along the Amur basin are some of the most valuable ecosystems, home to a huge variety of flora and fauna. These are important refuges for millions of migratory birds, including white storks and red-crowned cranes. The river basin is home to more than 5,000 species of vascular plants, 70 species of mammals and 400 species of birds. Rare and endangered species are found here, such as Amur tiger And amur leopard- the most iconic mammal species in the region. The waters of the Amur are home to a wide variety of fish species: about 100 species in the lower reaches and 60 in the upper reaches. Chum salmon, burbot and whitefish are among the most commercially important northern fish species.

Vilyui

Vilyui - a river in the Central and Eastern Siberia, flowing mainly through the Republic of Sakha (Yakutia) in eastern Russia. This is the largest tributary of the Lena, with a length of 2650 km and a basin area of ​​​​about 454 thousand km².

The Vilyui originates on the Central Siberian Plateau and first flows east, then south and southeast, and again east to its confluence with the Lena (about 300 km northwest of the city of Yakutsk). The river and adjacent reservoirs are rich in commercial fish species.

Kolyma

With a length of more than 2,100 kilometers and a basin area of ​​643 thousand km², Kolyma is the most big river Eastern Siberia, flowing into the Arctic Ocean. The upper reaches of this river system began to develop back in the Cretaceous period, when the main watershed between the Sea of ​​Okhotsk and the Arctic Ocean was formed.

At the beginning of its journey, Kolyma makes its way through narrow gorges with numerous rapids. Gradually, its valley expands, and below the confluence with the Zyryanka River, it flows through the wide swampy Kolyma Lowland, and then flows into the East Siberian Sea.

Ural

The Ural is a large river flowing in Russia and Kazakhstan, 2428 km long (1550 km in the Russian Federation), and a basin area of ​​about 231 thousand km². The river originates in Ural mountains on the slopes of the Round Hill and flows in a southerly direction. In the city of Orsk, it turns sharply west through the southern outskirts of the Urals, past Orenburg, and turns south again, heading towards the Caspian Sea. Its flow has a large spring maximum, and freeze-up lasts from late November to April. Navigation on the river is carried out to the city of Oral in Kazakhstan. The dam and hydroelectric power station were built on the Iriklinskoye reservoir, south of the city of Magnitogorsk.

The Ural Delta wetlands are particularly important for migratory birds as a primary refuge along the Asian Flyway. The river is also important for many fish species of the Caspian Sea, which visit its deltas and migrate upstream to spawn. In the lower reaches of the river there are 47 species from 13 families. The carp family accounts for 40% of the species diversity of fish, sturgeon and herring - 11%, perch - 9% and salmon - 4.4%. The main commercial species are sturgeon, roach, bream, pike perch, carp, asp and catfish. TO rare species include Caspian salmon, sterlet, nelma and kutum. The Ural delta and surrounding areas are home to about 48 species of animals, of which 21 species belong to the order of rodents.

Don

The Don is one of the largest rivers in the Russian Federation and the 5th longest river in Europe. Its basin is located between the Dnieper-Donets depression in the west, the Volga basin in the east, and the Oka River basin (a tributary of the Volga) in the north.

The Don originates in the city of Novomoskovsk 60 km southeast of Tula (120 km south of Moscow), and flows for a distance of about 1870 km to the Sea of ​​Azov. From its source, the river heads southeast to Voronezh and then southwest to its mouth. The main tributary of the Don is the Seversky Donets.

Table of the largest rivers of the Russian Federation

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A river is a natural stream of water that flows in the same place constantly or intermittently during the dry season (drying rivers). The place where a river begins is called its source. The source can be lakes, springs, glaciers. The place where a river flows into a sea, lake or other river is called an estuary. A river flowing into another river is called a tributary.

River mouths can be deltas and estuaries. Deltas arise in shallow areas of the sea or lake as a result of the accumulation of river sediments and have a triangle shape in plan. The river bed here branches into many branches and channels, usually arranged in a fan-shape. Estuaries are single-arm, funnel-shaped river mouths, expanding towards the sea (the mouths of the Thames, Seine,). Usually the part of the sea adjacent to the estuary has great depths, and river sediments are removed by sea currents. Low-water rivers sometimes end in blind mouths, i.e. do not reach the reservoir (Murgab, Tedzhent, Coopers Creek).

The main river with all its tributaries forms a river system. The territory from which the river collects surface water is called a basin. Each river has its own pool. Largest pools have rivers (more than 7 million km2), Congo (about 4 million km2), in Russia - (about 3 million km2). The boundary between river basins is called a watershed.

Flowing river water long time produces long and complex river valleys. A river valley is a concave, winding landform that stretches from source to mouth and slopes toward the mouth. It consists of a channel, floodplain, and terraces.

A channel is a depression in a river valley through which river waters constantly flow. A floodplain is a part of a river valley that fills with water during flood periods. The slopes of the valley usually rise above the floodplain, often in a stepped shape. These steps are called terraces. They arise as a result of the eroding activity of the river. The river bed usually has a sinuous shape in plan and is characterized by alternating deeper sections (reaches) with shallower ones (rifts). The meanders of the river are called bends, or meanders, lines greatest depths- fairway.

All the given characteristics of the river are its natural characteristics. In addition to them - and no less important - is a set of calculated characteristics that are closely related, and sometimes interspersed with natural ones.

Important characteristics of a river are its fall, slope, flow speed, flow and discharge. The fall of a river is the excess of its source above its mouth (the difference in heights of two points). Channel slope is the ratio of the fall to the length of the river. For example, the height of the source is 226 m, the mouth is 28 m, and the length is 3530 km. Then its slope will be equal to: 226 - (-28) / 3530 = = 7.2 cm/km. The falls and slopes of individual sections of the river are also calculated if their height and length are known. The fall and slopes, as a rule, decrease from the sources to the mouth; the flow speed depends on their magnitude; they characterize the energy of the flow.

Each river has middle and lower reaches. The upper reaches are characterized by significant slopes and high erosive activity, the lower reaches have the largest mass of water and lower speed.

The speed of a water stream is measured in meters per second (m/s) and is not the same in different parts of it. It consistently increases from the bottom and walls of the channel to the middle part of the stream. Speed ​​is measured different ways, for example, hydrological floats or hydrometric turntables.

The water regime of a river is characterized by water flow and runoff. Discharge is the amount of water passing along a river bed in one second, or the volume of water flowing through a cross-section of a stream in a unit of time. Typically, flow rate is expressed in cubic meters per second (m 3 /s). It is equal to the cross-sectional area of ​​the flow multiplied by the average flow velocity. Water consumption over a long period of time—a month, a season, a year—is called runoff. The amount of water that rivers carry on average per year is called water content.

The most abundant river in the world is the Amazon. Its average flow rate is 20 thousand m 3 /s, about 7 thousand km 3. In its lower reaches, the width of the Amazon in some places reaches 80 km. In second place in terms of water content is the Congo River (flow - 46 thousand m 3 / s), then the Ganges. In Russia, the most water-rich (discharge 19.8 thousand m 3 /s) and Lena (17 thousand m 3 /s). The most in the world is the Nile (with Kagera) - 6671 km, in Russia - the Amur (with Argun) - 4440 km.

Depending on the rivers, they are divided into two large groups: lowland and mountainous. Many rivers in the upper reaches are mountainous, while in the middle and lower reaches they are flat. Mountain rivers have significant drops and slopes (up to 2.4 and even up to 10 m/km), fast current (3-6 m/s), usually flow in narrow valleys. Sections of rivers with a rapid flow, confined to places where difficult-to-erode waters come to the surface, are called rapids. The fall of water from a steep ledge in a river bed is called a waterfall. The highest waterfall on Earth is (1054 m) on the Caroni River (a tributary of the Orinoco); Victoria on the Zambezi River (Africa) has a height of 120 m and a width of 1800 m. Plain rivers are characterized by slight falls and slopes (10-110 cm/km), slow flow (0.3-0.5 m/s), usually flow in wide valleys.

A significant portion of the water flow consists of dissolved salts and solids. All solid material carried by a river is called . It is expressed by the mass or volume of material that the river carries over a certain time (season, year). This is an extremely large river work. The average annual solid runoff, for example, of the Amu Darya is about 100 million tons of solid material. River sediments clog, fill reservoirs, and impede the operation of hydraulic turbines. The turbidity of the water depends on the volume of solid waste, which is measured in grams of the substance contained in 1 m 3 of water. The turbidity of river waters is the lowest (up to 20 g/m3), and the highest (500 - 1000 g/m3).

The most important characteristic of rivers is their nutrition. There are four sources of nutrition: snow, rain, glaciers, underground. The role of each of them in different seasons of the year and in different places not the same. Most rivers have mixed feeding. Rain is typical for rivers in equatorial and monsoon regions. Snow feeding is observed near rivers at latitudes with cold, snowy winters. Glacially fed rivers originate in high, covered mountains. Almost all rivers are fed to one degree or another. Thanks to them, the rivers do not dry out in the summer and do not dry up under the ice.

The regime of rivers largely depends on nutrition. River regime is a change in the amount of water flow according to the seasons of the year, fluctuations in level, and changes in water. In the annual water regime of rivers, periods with typically repeating levels are distinguished, which are called low water, high water, and flood.

Low water is the lowest water level in the river. During low water periods, the flow and flow of rivers are insignificant; the main source of nutrition is groundwater. In temperate and high latitudes there is summer and winter low water. Summer low water occurs as a result of the absorption of precipitation and strong evaporation, while winter low water occurs as a result of the lack of surface nutrition.

Flood is a high and prolonged rise in the water level in the river, accompanied by flooding of the floodplain. It is observed annually in the same season. During high water, rivers have the highest water content; this period accounts for most of the annual flow (up to 60-80%). Floods are caused by spring melting of snow on the plains or summer melting of snow and ice in the mountains and polar regions. Floods often cause long and heavy rains during the warm season.

Flood is a rapid but short-term rise in the water level in a river. Unlike a flood, a flood occurs irregularly. It is usually formed from rain, sometimes from rapid melting of snow or discharge of water from. Down the river, the flood spreads as a wave, which gradually fades.

Floods are the highest rises of water that inundate areas located in a river valley and adjacent low-lying areas. Floods are formed as a result of an abundant influx of water during the period of snowmelt or rainfall, as well as due to the blockage of the riverbed with ice during the period of ice drift. In the Kaliningrad region (Pregolya river) and (Neva river) they are also associated with the wind surge of water from the sea and the backwater of the river flow. Floods are common on rivers ( monsoon rains), on, Ohio, Ganges, etc. They cause great harm.

Rivers of cold and temperate latitudes in the cold season they freeze and become covered with ice. The thickness of the ice cover can reach 2 m or more. However, some sections of rivers do not freeze, for example, in a shallow section with fast current, or when rivers emerge from a deep lake, or on the spot large quantity sources. These areas are called polynyas.

The opening of a river in the spring, during which the movement of broken ice floes downstream the river is observed, is called ice drift. Ice drift is often accompanied by jams and jams. - accumulation of floating ice caused by any obstacles. Jams are accumulations of inland ice. Both cause a sharp rise in the water level, and when a breakthrough occurs, its rapid movement along with the ice.

The main source of nutrition for the rivers of the Black Sea-Caspian slope, like most rivers in the European part of the country, is melted snow water. However, the share of snow supply in the total annual runoff varies in different parts of this vast territory. There is a natural increase in the role of snow supply in the direction from the wetter and warmer west to the colder and more continental east. While in the west the share of snow supply does not exceed 40-50%, in the east and especially in the southeast (Lower Volga region) its share increases to 80-90%, i.e. approximately 2 times. At the same time, to the southeast the share of ground and rain nutrition decreases. An increase in the role of snow nutrition and a corresponding decrease in the share of other sources of nutrition also occurs in the direction from north to south.

Types of rivers in the European part of Russia

Depending on the ratio of individual types of food within the region, the following main types of rivers can be distinguished:

1. Rivers of mixed feeding with a predominance of snow (the share of snow feeding is less than 50%). The rivers of the west and southwest (Dniester basins) belong to this type. They are characterized by an increased role of rain and groundwater recharge (the latter in the Pripyat basin in some places accounts for up to 50% of the annual runoff).
2. Rivers are predominantly snow-fed (the share of snow-fed is from 50 to 80%). The vast majority of rivers in the region (the Dnieper, Don and Volga basins) belong to this type.
3. Rivers are almost exclusively snow-fed (the share of snow-fed is more than 80%). Small rivers of the Lower Volga region and the south of the steppe zone (the region of the Black Sea lowland) belong to this type. Here, moisture from summer rains is lost almost completely through evaporation and usually does not produce runoff, and the level groundwater lies deep, below the bottom of river valleys.
It must be borne in mind that the ratio of food sources depends on the size of the river, especially in the forest-steppe and steppe zones. The smaller the river, the less deeply its valley is cut, as a rule, and the less, therefore, its groundwater supply. Small rivers of the forest-steppe and steppe zones do not reach the level of deep groundwater and therefore are fed almost exclusively by melting snow. Thus, the smaller the river basin, the greater the share of snow supply.

The change in the share of spring (mainly runoff from melted snow waters) depending on the size of the catchment area can be seen from Table. 1, compiled according to data from K. P. Voskresensky.

Table 1. Change in the share of spring runoff depending on the size of the catchment area

Thus, on small rivers of the forest-steppe zone with a catchment area of ​​up to 50 km 2, and in the steppe - up to 1000 km 2, runoff occurs exclusively in the spring due to snow melting. In the Sal steppes, on rivers with a drainage area of ​​up to 10,000 km 2, flow occurs exclusively in the spring.

Regime of rivers in the European part of the country

The overwhelming majority of rivers in the region are characterized by the following main features of the regime: high spring flood, low summer low water, only occasionally interrupted by rain floods, and winter low water. On the rivers of the forest zone, in addition, the autumn flood is clearly visible, formed due to water from heavy rains. On the rivers of the forest-steppe and steppe zones, summer floods are extremely rare, and autumn floods are absent, since here, as noted above, moisture not only from summer, but also from autumn rains is almost completely filtered into the soil and spent on evaporation. This is a significant difference between the regime, for example, of the Upper Volga, located in the forest zone, and the Don, the basin of which is entirely located in the forest-steppe and steppe zones.

In the southern and especially in the southeastern parts of the region, where local watercourses are almost exclusively snow-fed, the rivers are characterized by high spring floods and almost complete or complete absence of flow in other seasons.

At sudden changes water content throughout the year, the river regime is characterized by large amplitudes of level fluctuations, reaching 16-17 m on the Volga, 18 m on the Oka, 10-12 m on the Don and 12-14 m on the Dnieper. On medium and small rivers, level fluctuations also significant - up to 6-8 m. The magnitude of surface runoff and the relative water content of rivers drop sharply in the direction from north to south. This, on the one hand, is explained by a decrease in the number of atmospheric precipitation, on the other hand, by a sharp increase in relative evaporation losses.

The rivers of the forest zone have the highest relative water content, where the runoff coefficient is on average 0.4-0.5, and the annual runoff module is 5-10 l/sec km 2. The rivers of the Carpathians and the western slopes of the Urals are particularly water-bearing, where the runoff module increases to 15-20 and even 25 l/sec km 2 (Vishera basin).

The rivers of the western part and especially Polesie, where the annual flow module, despite the large amount of precipitation, is equal to 4 l/sec km 2, are characterized by lower relative water content within the forest zone. This is explained by a very low runoff coefficient, which in turn is associated with the flat nature of the area and large losses of moisture through evaporation. IN forest-steppe zone evaporation losses increase significantly and the runoff coefficient decreases to 0.2-0.3, and the relative water content usually does not exceed 2-4 l/sec km 2.

In the steppe zone, approximately only 10% of precipitation goes to the formation of surface runoff, and 90% is spent on evaporation. Therefore, the runoff modules here are low and usually do not exceed 0.5-2.0 l/sec km 2. And finally, in the semi-desert zone (Caspian lowland), with low precipitation, only a small proportion (less than 5%) goes to runoff. The river network in these conditions is extremely rare or completely absent.

As you move south, not only the relative water content of rivers decreases, but its fluctuations also increase. While in the northern parts of the region (the Kama, Upper Volga, upper Dnieper basins) the amount of runoff over a long period of time fluctuates within relatively small limits, in the south in the steppe zone the differences in water content of individual years are more pronounced. This is confirmed by regular changes in the coefficient of variation of annual runoff from 0.2-0.3 in the north to 0.85 or more in the south.

The maximum water flows of the year are observed on most rivers during periods of spring floods. Summer and autumn rain floods are significantly lower in height spring flood. Only in the southwest (the Dniester and Prut basins and on the Ural rivers) the maximum of summer rain floods in some years can reach and even exceed the maximum of spring floods. The above is true only for relatively large rivers; on small watercourses, the intensity of rain floods increases sharply and from a certain limit, which reaches the catchment areas, rain maximums begin to prevail everywhere over snow peaks. The reason for this lies in the fact that in the European part of the country, particularly intense downpours can simultaneously cover only small areas.

While in the forest zone rain maxima can prevail over snow maxima only in very small basins - less than 50-100 km2, in the south in the steppe zone rain maxima are higher than snow maxima already on large rivers, with drainage areas of up to 4-5 thousand km. km 2. In very small basins (beams), the modules of rainfall maximums can reach very high values: for catchment areas; with areas of 0.4-0.5 km 2 - 50-70 thousand l/sec km 2.

The further you go south, the more shallow the rivers become during low water periods. In the north, in the forest zone, flow modules, even during low-water periods, do not fall below 1.0-1.5 l/sec km 2; in the south, in the steppe zone, the minimum flow in rivers is characterized by very low values ​​- up to 0.1-0.05 l /sec km 2; Many rivers dry up completely and their flow stops in the summer. In the basins of the upper Dnieper, Upper Volga and Kama, only small rivers with drainage areas of no more than 100-250 km 2 can dry out in the summer or freeze in the winter.

To the south, in the forest-steppe zone, much larger rivers, with catchment areas of up to 500 km 2, may dry up. Finally, in the steppe zone, flow may stop on rivers whose basin areas reach 5-10 thousand km 2. In cases where a river carries its waters through a semi-desert zone, the phenomenon of drying out is observed even in such relatively big rivers, like Embe (catchment area 45800 km 2).

Most rivers in the region experience freeze-up every year. Only in the extreme south and especially in the southwest (the Dniester and Prut basins) may there be no freeze-up in some years with mild winters. Freeze-up is relatively rare on the Danube.

Freezing of rivers begins earlier in the northeast of the region (in the Kama basin) - usually in the first half of November. From here, the freezing process gradually spreads towards the southwest, and in the extreme southwest (the Dniester and Prut basins) freezing is observed later - at the end of December or at the beginning of January.

The opening, on the contrary, begins earlier in the southwest (in the Dniester basin) - at the beginning of March - and from here it spreads to the northeast, where it occurs in the second half of April. Thus, the duration of freeze-up increases from 60-70 days in the southwest to 150-170 days in the northeast. As the duration of freeze-up increases, the thickness of the ice cover also increases.

In the direction from northeast to southwest, the long-term amplitude of fluctuations in the timing of opening and freezing also increases. In the Kama basin, for example, the difference between early and late does not exceed 40-50 days, and in the Dnieper basin it increases to 70-90 days. In the Dniester basin, in general, the concept of the amplitude of the periods of opening and freezing becomes uncertain, since in some years the Dniester may not freeze at all.

Water erosion of rivers

Let us dwell briefly on the characteristics of the erosion activity of rivers and their hydrochemistry. It has been noticed that the erosion activity of rivers increases in the direction from north to south. While in the forest zone the development of erosion is hampered by forests and swamps, in the forest-steppe and especially steppe zones, with their almost complete treelessness, as well as with large plowed slopes, the consequences of water erosion in some places acquire catastrophic proportions. Widespread loess-like soils, which are easily eroded, also contribute to the development of erosion. On rivers, this is manifested in an increase in the turbidity of their waters from 30-50 g/m 3 in the forest zone to 600-1000 g/m 3 in the steppe (Table 2).

Table 2. Changes in river water turbidity in various landscape zones

In small basins of forest-steppe and steppe zones, the annual removal of substances suspended in water often reaches enormous values ​​- up to 50-80 tons, and sometimes up to 250 t/ha; in this case, the most fertile soil particles are carried away. If we also take into account that gully erosion is widespread here, we can say that, in general, the erosive activity of water in the steppe and forest-steppe zones causes great damage to agriculture.

In the forest zone, all waters are fresh (mineralization less than 100 mg/l), soft and very soft (hardness 0-8°). In the forest-steppe zone, mineralization increases to 100-500 mg/l, signs of salinization appear, and waters become harder. In the steppe zone, all the waters of small rivers are mineralized to one degree or another (up to 500-1000 mg/l) and are characterized by high hardness (18-30°). Finally, in the semi-desert, mineralization and water hardness are even higher (mineralization increases to 1000-1500 mg/l or more, hardness exceeds 30°). At first glance, the significant excess of the chemical runoff over the suspended sediment runoff seems somewhat unexpected. In the rivers of the forest zone of the region, the runoff of chemically dissolved substances is 2-4 times greater than the sediment runoff.

Rivers are natural water streams flowing in the depression they have created, the bed, and are fed by surface and underground runoff from their territory and basins. A “river basin” usually means an area bounded by a watershed line, the flow from which flows into the main river and its tributaries. Rivers have a source - the place where the river (lake, spring) begins and an estuary - the place where the river flows into another river, lake, sea (mouths can be “blind” or “dry”). The main river and its tributaries form a river system. Between river basins there is a border - a watershed. The set of all watercourses and reservoirs of a territory is called a hydrographic network.

The most important characteristics of a river include its water content, the structure of flow according to food sources, the type of water regime, the length of the river, the catchment area, the slope and fall of the river, the width and depth of the channel, the cross-sectional area, the speed of water flow, its temperature, chemical composition water, etc.

All rivers are divided into mountain rivers with a fast flow, flowing in narrow valleys, and lowland rivers with a characteristic slow flow and wide terraced valleys.

According to the sources of river nutrition and the distribution of their flow by season, 38 types of water regime are distinguished.

Rivers are characterized by a very uneven distribution of flow over time. The main phases of the water regime of rivers are high waters, floods and low water.

The natural mineralization of most rivers is relatively low - usually less than 200 mg/l. Their water would be quite suitable for drinking if it were not contaminated with waste from economic activities.

River- a natural constant water flow flowing in a depression created by it - a channel. In turn, the channel is only part river valley– a linearly elongated depression, along the bottom of which a river flows in accordance with the slope of the bed. In mountain rivers, the bottom of the valley is almost completely occupied by the river bed; in lowland rivers, it is occupied by the bed and floodplain. Channels most often have a meandering shape, but large rivers and rivers in the foothills can branch into branches. Channels of a relatively rectilinear shape are less common.

Every river has source- the place where the river originates, where the river bed acquires a clearly defined outline and a current is observed in it. Rivers can originate from springs, glaciers, or lakes. It is sometimes said that rivers are also formed by the confluence of two other rivers. In fact, a new river toponym, that is, a new name, can arise in this way, while the constituent rivers, no matter what they are called, have typical sources. Example: the rivers Biya and Katun give rise to the Ob. The Amur begins at the confluence of the Shilka and Argun rivers.

Estuary– a place where a river flows into another river, lake or sea. A river may have a “dry mouth”, i.e. it may end at a “blind end” if in the lower reaches the slopes of the territory through which the river flows are very small, the water consumption for evaporation, filtration into the ground or for irrigation is high (Chu Tarim rivers , Murgab, etc.).

Hydrographic network– a set of watercourses and bodies of land of natural origin (rivers, lakes, swamps) and reservoirs within a territory. River network– a set of rivers located within this territory; it is part of the hydrographic network.

The river network consists of river systems.

River system- the main river with its tributaries. For example, a significant part European Russia occupied by the Volga river system with its tributaries. Usually the longest and deepest river is considered the main one. But a number of names of the main rivers were strengthened historically; the main river became the one that people knew earlier and better. For example, the Volga is inferior in length to both the Oka and Kama from its source to its confluence with them; The Missouri is longer and deeper than the main Mississippi River. According to one classification, the tributaries of the main river are called tributaries of the first order, their tributaries are called tributaries of the second order, etc. According to another classification (by the American hydrologist Horton), a river of the first order (elementary river) is considered a river without tributaries, rivers of the second order are formed at the confluence of two rivers of the first order, rivers of the third order - at the confluence of two rivers of the second order, etc. Thus, the higher the order number of the river, the more complex nature has a river system. There are other approaches to classifying rivers.

River basin- Part earth's surface, which includes this river system. The largest basin is the Amazon - 7.2 million km 2. drainage basin - the area of ​​land from which a river system collects its waters. It may be smaller than a river basin if there are drainage areas within the latter (for example, as in the Irtysh basin).

Watershed– a line on the earth’s surface dividing the runoff of precipitation along two oppositely directed slopes. All Earth can be divided into two main slopes along which water flows from the continents: 1) into the Atlantic and North Arctic Oceans; 2) in Quiet and Indian Oceans. Between these two slopes passes World watershed, or the Main Divide of the Earth. The watersheds between the peripheral areas and the internal drainage areas are called internal watersheds. Watersheds between oceans and seas separate areas of land, the flow from which is directed to different oceans or seas. River watersheds are the dividing lines of river systems. Watersheds are better defined in the mountains than on the plains.

Very rarely on accumulative plains it is impossible to draw watersheds at all, since the mass of water from one river is divided into two parts, heading to different river systems. This phenomenon of bifurcation of the flow is called river bifurcation. A striking example of a bifurcation is the bifurcation of the Orinoco River in the upper reaches: one of them. which retains the name Orinoco, flows into the Atlantic Ocean, the other, Casiquiare, flows into the Rio Negro River, a tributary of the Amazon. There are bifurcations of rivers flowing through the Primorsky lowlands of northeast Russia between the mouths of the Indigirka and Kolyma. A unique case of bifurcation is demonstrated by the Onega in its lower reaches, being divided into two branches by a huge island composed of bedrock. The branches diverge over a distance of up to 20 km and converge again near the mouth.

Each river has certain morphometric characteristics.

River length– the length of the river bed from source to mouth.

River meandering is determined by the coefficient of tortuosity of the river bed (K) - the ratio of the length of the river along the bed ( l) to the length of the river along the valley bottom (L). K= l/L. The tortuosity coefficient is usually calculated for individual river sections.

Density of the river network (D) is the ratio of the total length of all rivers of the river system to the river basin (F): D=ΣL/F km/km 2 .

Longitudinal profile The river is characterized by the longitudinal profile of the bed of the channel (it always looks like a wavy line) and the water surface (a smoother line). The fall of a river is the height difference between the source and the mouth of a river or the difference in heights of two points on the water surface along the length of the river ( h m).

River slope– the ratio of the magnitude of the river fall to the length of the river ( l) or to the length of a certain section of the river ( i=h/l). The slope of a river is a dimensionless quantity. Its values ​​are very small, especially on lowland rivers. Thus, the slope of the Oka in the middle reaches is only 0.00009, so the slope is often replaced by a kilometer drop - a value physically identical to the slope, but expressed in m/km. The kilometric fall of the Oka is 0.09 m/km.

The longitudinal profiles of rivers are different depending on the properties of the rocks composing their beds and slopes. In most lowland rivers flowing through loose sediments, it has the appearance of a concave curve, flattening towards the mouth. In mountain rivers, the longitudinal profile of the channel is usually stepped, and the steps are associated with unequal erosion of the rocks composing the channel. In places where rocks are hard to erode, profile breaks are observed in the form of thresholds or steep ledges, which are associated with rapids or waterfalls, respectively. There are also rapids on lowland rivers, for example the famous Dnieper rapids, formed when the Dnieper crossed the crystalline ledges of the Ukrainian shield. The length of rivers flowing from lakes is typical of convex or convex-concave longitudinal profiles.

Water section of the river is the cross section of a riverbed filled with water.

Live cross section of the river– cross-sectional area of ​​the flow. That part of the water cross-sectional area where there is practically no flow is called dead space.

The elements of the river’s water section are: its square (ω); channel width(IN); maximum depth(h max), average depth, which is calculated by the formula h medium = ω/V; wetted perimeter(P) – the length of the underwater contour of the river from the edge of one bank to the edge of the other bank; hydraulic radius(R) – ratio of the water cross-sectional area to the wetted perimeter: R= ω/P. The hydraulic radius characterizes the shape of the channel in cross section: for lowland rivers it is almost equal to the average depth. The width of the river and maximum depth are determined by direct measurements. Based on slopes, flow velocities and the general hydrological regime in rivers, three flow sections can be distinguished: upper, middle and lower.

The upper reaches of many rivers are mountainous, and even among lowland rivers they are most often located on hills. There are high current speeds here, a rocky bottom, rapids, rapids, and sometimes waterfalls are common, low temperature water. Mountain rivers have a similar character almost throughout their entire length, excluding where they cross intermountain depressions. In sections of the middle reaches of lowland rivers, flow speeds are lower; the bed is composed of sand, gravel, and pebbles. In the lower reaches of the river, they are characterized by low flow speeds, long floods, small sediments, and low banks.

Literature.

1. Lyubushkina S.G. General Geography: Textbook. a manual for university students studying specialties. "Geography" / S.G. Lyubushkina, K.V. Pashkang, A.V. Chernov; Ed. A.V. Chernova. - M.: Education, 2004. - 288 p.