Australia is the smallest continent in the world, located in southern hemisphere. The area of Australia with the islands is less than 8 million square meters. km, the population is about 23 million people.
The western and southern coasts of the mainland are washed by the Indian Ocean, the north by the Timor and Arafura seas of the Indian Ocean, and the east by the Coral and Tasman seas of the Pacific Ocean. The extreme points of Australia: in the north - Cape York, in the west - Cape Steep Point, in the south - Cape Southeast, in the east - Cape Byron. The distance from the extreme northern to the extreme southern points of the mainland is 3200 km, from the western to the eastern - 4100 km. Parallel to the eastern coast, the Great Barrier Reef stretches for 2300 km.
The coast of the mainland is slightly indented. There are large gulfs Great Australian in the south and Carpentaria in the north. In the northern part of Australia there are two peninsulas with the largest area, Cape York and Arnhemland. This continent includes adjacent islands - Tasmania, Melville, Kangaroo, etc.
The mainland lies on the ancient Australian platform, which passes into the East Australian fold belt. The average height of Australia is 215 m above sea level, and most of the mainland is occupied by plains and up to 95% of the territory is below 600 m. In the eastern part of the mainland, the Great Dividing Range stretches along the coast, which includes several flat-topped mountain systems. In the western part of the continent there is a plateau up to 500 m high with table mountains and ridges, in the central part there is a lowland with a large lake Eyre. On the territory of the mainland there are deposits of minerals, such as hard and brown coal, copper, iron ore, bauxite, titanium, polymetallic and uranium ores, diamonds, gold, natural gas, oil.
The main part of Australia is located in the tropical climate zone, the northern regions are in the equatorial zone (with a hot climate and frequent summer rains), the southern regions are in the subtropics (with a predominance of precipitation in winter). In the middle part of the continent, 70% of the territory is dominated by a desert and semi-desert climate. The east coast has a hot tropical maritime climate, where precipitation occurs mainly in the summer. The amount of average annual precipitation decreases from east to west.
Large river systems of the mainland - Murray, Darling, Flinders. characteristic feature Australia is the presence of screams - rivers that fill with water only after heavy rains.
On the vast interior spaces of the mainland are the Great Gibson Desert, Victoria, the Great Sandy Desert, etc. Salt lakes can often be seen here. A belt of semi-deserts with shrubs extends around the deserts. In the northern, eastern and southeastern regions, semi-deserts are replaced by savannahs. In the mountainous regions and along the coasts, forests of palm trees, tree ferns and eucalyptus trees grow. Among wild animals in Australia, rabbits, pigs, wild dogs are found in large numbers. Among endemic animals there are many marsupial forms (kangaroos, wombats, marsupial wolves, marsupial moles).
The entire territory of the mainland and the island of Tasmania is occupied by the country of the Commonwealth of Australia. The state is divided into six states: Victoria, New South Wales, Queensland, Western Australia, South Australia, Tasmania. The number of indigenous people is only 2% of the total population, the rest of the inhabitants are the descendants of Europeans and Asians who colonized the mainland after its discovery in the 17th century. High level development Agriculture and the mining industry have brought the country to a leading position as a supplier of wheat, coal, gold, iron ore to the world market.
Rivers Eurasia carry almost half of all the waters flowing from the land of the planet into the World Ocean. In terms of river runoff, the continent surpasses all continents. Of the 14 greatest rivers in the world (more than 3 thousand km long), most of them are located in Eurasia: Yangtze, Huang He, Mekong, Indus, Lena, Ob, Yenisei, Volga.
Rivers are unevenly distributed across the mainland. The most powerful river systems are located in Asia - in its northern, eastern and southeastern parts. In the central regions, the river network is almost absent. Europe is dominated by small rivers. The largest rivers of Eurasia originate in the depths of the mainland high in the mountains and spread in all directions to the marginal plains. In the upper reaches they are all mountainous, in the lower reaches they are flat, calm and wide. Flowing out of the mountains, the rivers lose speed, expand the valley and deposit the material brought in it - alluvium. Alluvial are the largest plains of Eurasia.
Rivers of Eurasia are extremely diverse in terms of food types and runoff regime. The same river, crossing different climatic zones, feeds on water from different sources in its different sections, overflows with floods and becomes shallow at different times. Most of the rivers have atmospheric feeding: mixed - snow and rain or predominantly rain. These are the rivers of the outskirts of the mainland with non-continental climates. High water on different rivers occurs at different times of the year, depending on the onset of the rainy season or the snow melting. In the rivers of continental regions, groundwater plays the main role in nutrition. During low water, some dry up completely. Rivers originating in the mountains of Europe, in the center, in the east and southeast of Asia, are fed by the waters of melting glaciers. Asian rivers flowing through permafrost also have a glacial type of nutrition.
River basins. Rivers carry water collected from 65% of the territory of Eurasia to all four oceans of the planet. A third of the continent's surface has no runoff into the oceans. Accordingly, the territory of Eurasia is divided into five drainage basins. Four of them are ocean basins, and the fifth is an internal runoff basin. This is the largest internal runoff basin on the planet.
Swimming pool Arctic Ocean occupies the northern edge of Eurasia. "Record holders" of the basin: Lena - has the longest length - 4400 km; the Ob (3650 km, with the Irtysh 5410 km) - the largest catchment - about 3000 km 2 (Fig. 39); Yenisei (from the confluence of the Big and Small Yenisei - 3487 km) - carries the largest amount of water into the ocean - 630 km 3 / year (Fig. 40). These rivers originate in the mountains. They flow to the ocean along the plains - low or elevated, from south to north - crossing several natural areas. A significant part of their valleys is located in the permafrost zone. They feed on melted snow, rain and glacier waters. In winter they freeze, and many of their medium-sized tributaries freeze to the bottom.
Basin rivers Pacific Ocean - Yangtze (6380 km) (Fig. 41), Huang He (4845 km), Mekong(4500 km) (Fig. 42), Amur(2850 km) - have a monsoon type of regime and are distinguished by high water. In the summer, when the rainy season begins and the snow melts in the mountains, up to 80% of their annual runoff falls. The water level at this time rises by 20-40 m. Floods are accompanied by severe floods. At this time, the rivers flood their valleys and fill them with a thick layer of loose sediments. The longest river on the continent second only to the Nile, the Amazon and the Mississippi, Yangtze. It begins in Tibet, breaks through rapids into the alluvial plain, where it flows among boundless lakes and swamps. At the confluence with the East China Sea, it forms a narrow long estuary - a funnel-shaped extended mouth. It is formed by the force of the sea tides rising up the river for several hundred kilometers. By the rivers of the basin indian ocean also monsoonal. The largest are Indus (3180 km), Brahmaputra (2900 km) (Fig. 43), Ganges(2700 km), Tigris, Euphrates- originate high in the mountains. Bo Ђ Most of their valleys lie in foothill troughs, and the rivers tirelessly fill them with alluvium. Its thickness in the Ganges valley reaches 12 km. The Ganges-Brahmaputra system in terms of water content is the third after the Amazon and the Congo: 7700 m 3 of water is carried into the ocean every second. 500 km from the ocean, the Ganges begins to form branches of a giant delta - the largest on the globe (more than 80 thousand km 2 in area).
From the rivers of other river basins Atlantic Ocean are diverse. They do not form large systems, have a smaller and more uniform flow, all possible power sources. Some of them freeze in winter, while others do not freeze over. Polomaputra (space image)
water and floods occur at different times. The largest river Danube(2850 km) - begins in the Black Forest mountains and flows through the territory of nine countries. Mountainous, rapids in the upper reaches, in the middle and lower it becomes a typical flat river - calm, with a wide floodplain and numerous oxbow lakes. The river cuts through the Carpathians in a narrow valley and, splitting into branches, flows into the Black Sea.
Swimming pool internal runoff occupies the central part of the mainland. Its rivers are usually short and do not form a dense network. They feed mainly on groundwater and often do not bring water to rare lakes, getting lost in the sands of deserts.
Not at all typical for the basin is its main river Volga(3530 km) - largest in Europe. It crosses the East European Plain from north to south. In the upper and middle reaches, the river is very full-flowing - it is fed by abundant waters of melted snow and rain. To the south, they dry up, but the consumption increases - for evaporation and household needs. The Volga flows into the Caspian, forming a powerful delta consisting of hundreds of channels and islands.
lakes Eurasia are numerous and varied. They are unevenly distributed over the territory and differ in the origin of the basins, size, nutrition, temperature regime, salinity.
The northern part of the continent, covered by an ancient ice cover, is dotted with glacial lakes. The largest (including the largest in Europe Ladoga and Onega lakes) occupy tectonic troughs deepened by the glacier. There are also many glacial lakes in the mountains of Central Asia and in the Himalayas. Distributed in southern Europe, western and southeastern Asia karst lakes. Far East and the Japanese islands are rich volcanic lakes. Widespread in river valleys floodplain old lakes. A significant part of the Eurasian lakes have basins tectonic origin. This is the largest lake in the world - the Caspian, and also Aral and Balkhash. Their depressions are the remains of the ancient Tethys Ocean. The largest lakes in central Europe - Constance and Balaton- located in foothills. Areas of continental rifts occupy the deepest lakes - Baikal (1637 m) and The Dead Sea. Lake in a tectonic basin Issyk-Kul.
The lakes of areas with a humid climate are fresh, those with a continental climate are salty to varying degrees. The salinity of endorheic lakes is especially high.
The surface of this drainless lake in Arabia is the lowest place on Earth’s land, 405 m below sea level. In some years, the water level drops to -420 m, and salinity, usually 260-270 ‰, increases to 310 ‰. Organic life in the waters of the lake is impossible, hence its name - the Dead Sea (Fig. 45).
The groundwater. Swamps. The underground waters of Eurasia are concentrated in large basins. East and Southeast Asia are especially rich in them. The wide distribution of swamps and wetlands is another feature of Eurasia. Bogs are typical in the tundra and forest-tundra, in the permafrost zone, and are very widespread in areas with a monsoon climate.
permafroston no continent planets(except Antarctica) not as widespread as in Eurasia. In the Asian part of the continent, it extends south to 48°N. w (Fig. 47). The permafrost was formed during the ancient glaciation. The modern climate in high latitudes contributes to its preservation (relic permafrost), and in the inland regions of the temperate zone - to its formation (modern). The thickness of frozen rocks reaches its greatest thickness in the upper reaches of the Vilyui River in Yakutia - 1370 m.
Using Figure 47, compare the distribution of permafrost in North America and in Eurasia, in Europe and in Asia. What explains the differences in its distribution?
Glaciation in Eurasia, it is significant in area - 403 thousand km 2, but it accounts for only 0.75% of the mainland. Almost 90% of the glaciers of Eurasia - mountain . In Europe, the most powerful mountain glaciation is in the Alps, in Asia - in the Himalayas (30 times more extensive than the Alpine). Integumentary glaciation is developed on the northern islands.
In the Caucasus, in Scandinavia, in the Polar Urals, Taimyr, northeast Siberia, Kamchatka, the Japanese islands, glaciation is facilitated by the oceanic (or coastal) position of the mountains, which makes it possible to retain precipitation. The formation of glaciers in Central Asia - in the Pamirs, Tibet, Kunlun, Karakorum, Tien Shan - is hindered by the dryness of their continental climate, but is facilitated by the enormous height.
Rice. 47. Distribution of permafrost
Changes in the state of water bodies under the influence of economic activity. The huge water wealth of the mainland is intensively used in the economy. However, due to the uneven distribution of inland waters across the territory, some regions experience an extreme lack of water resources, in others there is a problem of excessive surface moisture.
The shortage of water resources is especially acute inside the continent - in the basin of internal flow. Farming and people's lives here are possible only with artificial irrigation - irrigation. Often the water of the rivers is withdrawn completely, depriving water bodies of internal flow. It calls the chain environmental issues: soil salinization, increased wind erosion, desertification. Over the past decades, many small rivers and lakes have disappeared from the map of Eurasia, and some large rivers, for example Amu Darya and Syrdarya in Central Asia, they cannot carry their waters to the Aral Sea, which has turned into several small lakes because of this.
To remove excess moisture from the swampy woodlands of Europe and the lowlands of the Southern and South-East Asia carry out drainage works . Often, drainage that does not take into account the hydrological regime of biocenoses entails a chain of negative environmental consequences. The continental climate is growing, peat bogs are being destroyed, plant and animal species are disappearing forever, small rivers and lakes are drying up, and soil erosion is intensifying.
Intensive management leads to pollution of surface and groundwater with pesticides, mineral and organic waste, synthetic substances, oil products. "Infected" harmful substances The "circulatory system" of the mainland, impregnating the surface rocks, transfers these pollutants to long distances, spreading the "infection", and then takes it to the oceans. Despite the fact that the most densely populated regions of Eurasia are located in the basins of the largest rivers, in many of these areas there is an acute shortage of water resources, including clean water.
As a result of global warming, one of the causes of which is human economic activity, there is a rapid degradation of permafrost, intensive melting of glaciers, which leads to a gradual rise in the level of the World Ocean.
Bibliography
1. Geography Grade 9 / Tutorial for the 9th grade of institutions of general secondary education with the Russian language of instruction / Edited by N. V. Naumenko/ Minsk "People's Asveta" 2011
K.S. LAZAREVICH
In No. 5/2006, diagrams of the river systems of Russia were printed. The experience turned out to be successful: the schemes allowed teachers to navigate the difficult (and very confusing textbook authors who do not take the trouble to think about the numbers) question about “the longest rivers” and “the longest watercourses” in Russia or in its individual territories.
It publishes schemes for all continents, built on the same principle as the schemes for Russia. Schemes allow you to set the length of rivers, compare rivers and systems with each other, make a visual representation of river systems and watersheds of the seas.
Within the scheme for each continent, the rivers are placed in the order in which their mouths are located along the coast of the World Ocean, bending around the territory in a clockwise direction. Rivers that do not flow into the World Ocean are given after all, on a gray background.
The rivers - the main ones and their tributaries - are depicted by vertical lines. The flow of rivers is everywhere from the bottom up, so that the left tributaries and components of the rivers are on the left, the right ones are on the right. The lengths of the rivers are given on a scale, they are depicted by vertical lines, the horizontal segments are given only to show the ratio of the rivers, and have no conditional length.
The numbers written on the diagram at the sources of the rivers and at the horizontal segments indicate the distances along the channel from the mouth of the main river; the numbers written along the vertical segments indicate the length of these segments; all values are in kilometers. Along the upper frame of the scheme, reservoirs are marked, where the rivers flow. All signed figures are taken from reference books; It should be borne in mind that for little-studied territories (for example, in Africa, South America), the lengths of many rivers are given with an accuracy of hundreds or even thousands of kilometers. If you want to determine the distances that are not signed on the diagram (for example, between the mouths of tributaries), use the scale bar. But at the same time, remember that such measurements will only give an approximate result: the constructions were made by measuring on the map.
It is better to use the scheme with a map in front of your eyes, then the relative position of the rivers will be clear. In the comments to the diagram, only those places that may cause doubt are explained: unusual forms of mouths and the questions that arise in connection with this about the lengths of rivers; the flow of a river from one drainage basin to another, the temporary drying up of rivers.
Eurasia is the only continent where the drainage basins of all four oceans are located.
River systems are placed in the order of their mouths along the coast of Asia, from the northern end Ural mountains, skirting the continent, to the Sea of Azov. Next comes Europe - first south, then west and north. At the end of the diagram - the rivers of endorheic basins. The Jordan River in Western Asia, although very famous, is not shown, its length is only 250 km, that is, less than a centimeter in the diagram.
AT Asia the rivers of the Arctic Ocean basin flow through the territory of Russia, only some rivers of the Ob and Selenga systems in the Yenisei system begin outside our country.
The longest river in Asia and Eurasia, the Yangtze (other names are Changjiang, Yangtzyjiang), flows in the Pacific Ocean. The Huaihe River, which flows into it in its lower reaches, carries and deposits a lot of solid material (sand, clay), so the channel mainly lies above the adjacent plain, which often caused catastrophic floods, the river flowed either to the Yangtze or to the Yellow River. After the construction of the irrigation system in the 50-60s of the twentieth century. The threat of flooding has been largely eliminated, but part of the flow of the Huaihe continues to flow into the Huanghe, which is reflected in the diagram.
The Mekong River flowing into the South China Sea is one of the longest rivers in Asia, full of water, but the basin area is very small (with a length of 4.5 thousand km, the average width of the basin is 180 km), since the system of parallel ridges of the Sino-Tibet Mountains creates a series of isolated long and narrow watersheds.
The Ganges and Brahmaputra flow into the Bay of Bengal of the Indian Ocean, forming a common delta, the left channel of which is called Meghna, or Meghna. In reference books, the length of the Ganges is 2700 km, the Brahmaputra - 2900 km; apparently, Meghna is included in this length, on the basis of which the scheme is built.
The Tigris and Euphrates rivers in historical times flowed into the Persian Gulf separately, but then merged and formed the Shatt al-Arab river 195 km long.
Of the rivers flowing into the seas of the Atlantic Ocean, we note only the Turkish Kyzylyrmak and our Kuban; the latter is assigned to Asia, as it flows south of the Kuma-Manych depression.
Europe is studied at school in more detail than other parts of the world, many geographical features of Europe are constantly heard, so the scheme also includes small, by the standards of other territories, but well-known rivers. Of the rivers of Europe, only the Volga and Danube can be compared with the largest Asian rivers, although they are significantly smaller.
Europe is essentially a peninsula of the Eurasian continent. Within its limits, Western Europe, located outside the former USSR, and Eastern Europe, within its borders, stand out.
In Eastern Europe, mostly flat, rivers flow from its central part into the Azov, Black, Baltic, White and Barents Seas, as well as into the Caspian Sea, which is not connected to the ocean. From the center of the Russian Plain to the seas - one and a half to two thousand kilometers, and a river two (Dnepr, Don), or even three and a half thousand kilometers long (Volga) is not surprising.
And in the long and narrow Western Europe there is generally no point more than 600 km from the sea, and almost all rivers are short. Only the Danube, starting less than four hundred kilometers from the Mediterranean and five hundred from the North, managed to go half Western Europe along and get almost three thousand kilometers to the Black Sea. Rivers south of the Danube flow into the Mediterranean Sea, north - into the North and Baltic. To the west of the source of the Danube, the watershed runs through southern Europe - these are the Alps, the Central French Massif, the mountains of southern Spain (Cordillera Betica, Sierra Nevada), and the rivers that flow into the Mediterranean Sea are rather short, and longer ones flow directly into Atlantic Ocean, in the Bay of Biscay and the English Channel. That is why the Mediterranean Sea is somewhat saltier than the Atlantic Ocean. An exception from the rivers flowing into the Mediterranean is the Ebro, which, starting in the Cantabrian mountains, just fifty kilometers from the Bay of Biscay, cuts off the entire Iberian Peninsula, bravely breaks through to the Mediterranean Sea and, after passing 928 km, flows into it.
On the diagram, the French rivers Garonne and Dordogne, which form a common Gironde estuary 75 km long, can cause difficulty. The length of both rivers is counted from the outlet of the Gironde to the Bay of Biscay.
The scheme of the river of endorheic basins is being completed. The Caspian Sea washes the southeastern outskirts of Europe only for a short distance, but the drainage basin of the Caspian occupies 1/7 of Europe, and the Volga is certainly in first place among European rivers in terms of basin area.
The Amu Darya and Syr Darya flow into the Aral Sea. But that is why the Aral Sea dies, because these rivers do not flow into it all year long - their water is taken apart for irrigation; the channels in the lower reaches are shown by a dashed line. The bed of the Tarim (in the upper reaches of the river is called Yarkand) is very unstable, the Tarim only occasionally feeds Lake Lobnor, sometimes it goes into other water bodies or into the ground, so we can only speak about its length approximately.
The river network belongs to the basins of the Atlantic and Indian oceans. The Nile system is located in the eastern part of the continent, very close to Indian Ocean, but the Nile flows into the Mediterranean Sea - the sea of \u200b\u200bthe Atlantic Ocean.
The Volta River, which flows into the Gulf of Guinea of the Atlantic Ocean, was previously formed from the confluence of the White Volta and the Black Volta; the latter is longer and is considered the main source of the Volta. Now that the Volta reservoir has been created (the largest in the world in terms of area, almost 400 thousand km 2), the White and Black Volta flow into it, and the Volta River begins from the dam of the reservoir.
North America
The rivers of North America belong to the basins of three oceans. The great rivers Mackenzie (in the Beaufort Sea) and Nelson (in the Hudson Bay) flow into the Arctic Ocean. To the south, the relief of the continent predetermines a sharp asymmetry of the river network: the basin of the Atlantic Ocean is much larger than the basin of the Pacific. The largest river system of the continent, the Mississippi system, belongs to the Atlantic Ocean.
The river system that creates runoff from the Great Lakes has no analogues in the world. It does not have a single river longer than 1000 km, but in general the system, consisting of four lakes and five rivers, is only slightly inferior in length to the Volga. (Which of the Great Lakes was not included in this system and why?)
The continent is washed by two oceans, and the length of the coastline of the oceans does not differ much. Nevertheless, all the rivers included in the scheme refer only to the Atlantic Ocean basin - directly to the ocean or caribbean, and there is not a single river of any length that flows into the Pacific Ocean. As in North America, only to a much greater extent, the asymmetry of the relief is manifested, the position of the interoceanic watershed is very close to the western margin of the mainland. The diagram shows a bifurcation - the division of one river into two: in the upper reaches of the Orinoco, the 410 km long Casiquiare River separates from it, flowing into the Rio Negro - a tributary of the Amazon; the broken arrow on the diagram shows where the Casiquiare flows into, but, of course, it is impossible to measure the distance along this arrow. We have already met with a similar division of the river in the Yangtze system, but there the phenomenon is temporary.
Australia
Geography textbooks say that Australia is the driest continent. This is confirmed by the scheme: there is only one large river flowing into the ocean - the Murray. And is it so big if it carries about 10 km 3 of water into the ocean per year? For comparison: the Amazon - almost 7000, the Lena - more than 500, the Volga - 250. And there is also Coopers Creek, which reaches Lake Eyre only during heavy summer rains, otherwise it just goes into the ground somewhere halfway.
Tasks for working with diagrams,
printed on p. 10–18
Give assignments to students little by little; it is up to the teacher to indicate or not to indicate in which river system the solution should be sought; it is quite possible that the same teacher in one class will give additional explanations, but not in another.
1. Determine the distances along the rivers between characteristic points of rivers of the same system; such points can be the sources of different rivers, the mouths of tributaries and the main river, the exit of the river from the lake, etc. For example:
From the source of the Don to the mouth of the Seversky Donets;
From the source of the Tisza to the source of the Danube;
From the mouth of the Saone to the exit of the Rhone from Lake Geneva;
From the source of the Maranyon to the source of the Ucayali (remember which river system they belong to).
There can be many tasks of this type. Invite students to create several of these tasks on their own. Let them familiarize themselves with how the diagrams were drawn up (the introductory part of the explanatory text to the diagrams), and answer which of the tasks you proposed and which of those compiled by them can be solved exactly, which - only approximately and why.
2. When solving each example from task 1 mark which rivers, up or down their course, you move from the starting point to the final point.
3. Using any cards, arrange on the schemes of the rivers of the city.(Let the teacher offer a list of cities himself. Considering that in the next task it is proposed to measure the distances between cities, several cities should be selected in the same river system.) If students do not know where to look for these cities, let them look in the index of geographical names of the atlas . If the city is located on both banks of the river or you do not know which bank it is on, put the circle on the line denoting the river, if on one bank, then on the corresponding side of the line.
Which of these cities did you manage to draw exactly, which approximately? Why?
4. Measure at least 10 distances between by you river cities. Which of these distances did you manage to measure accurately, which approximately? Why?
5. Place a north-south arrow next to each river system. The rivers are winding, so it can only be placed approximately, given the general direction of the main river. For the Mississippi system, place (dashed) the second arrow corresponding to the Missouri source being taken as the main source.
6. Check black triangle in diagram mouths of rivers with deltas. Not all deltas are visible on the map, indicate only those that are expressed to scale on physical maps of the continents and parts of the world in school atlases.
In the scheme of Russian rivers (“Geography”, No. 5/2006), in the system of the Northern Dvina, Lake Kubenskoye and the Kubena River flowing into it were skipped. If you use this diagram, please supplement it, just remember that the diagrams in that issue and here are built on different scales.Remember the importance of water for other components of nature and for humans. What properties does water have? Which of them are geographically significant? What bodies of water are land waters?
Distribution of inland waters. Water is distributed across the continents extremely unevenly. There are areas where there is an abundance of rivers, lakes, there are extensive swamps, and in some areas there is practically no surface water, except for rare drying lakes. Of all the continents, the most "wet" (water-provided) is South America. If all the waters flowing down from this continent in a year are distributed in an even layer over its area, then a layer of water more than 500 mm thick will be obtained. This quantity is called the sink layer (8.1). In Antarctica, almost all water is in solid form, and does not flow into the ocean, but collapses in large blocks, forming icebergs. But in terms of volume fresh water Antarctica is many times larger than all the continents combined. It has been calculated that the reserves of fresh water contained in the Antarctic ice are approximately equal to the flow of all the rivers of the Earth for more than 500 years.
The distribution of inland waters over the territory of the continents most of all depends on the climate, but other factors also play a role. The distribution of rivers, lakes, swamps, glaciers, the shape of river valleys and lake basins, the conditions for the occurrence of groundwater are affected by the relief and geological structure of the area. For example, even with low rainfall, swamps can occur if the terrain is flat and difficult to drain.
All types of inland waters play a huge role in nature and in people's lives. However, the most prominent place is occupied by rivers.
Rivers. On all continents of the Earth, except for Antarctica, there are large and small river systems. South America has the most extensive river network, receiving the most precipitation.
There are almost no territories on this continent devoid of rivers. The huge basins of the Amazon, Orinoco, Parana occupy most of the mainland (8.2). Most rivers originate in the mountains, cut through mountain ranges and high plateaus and plateaus, forming rapids and waterfalls. Then they come out onto flat plains, overflow widely, turn into a dense network of water arteries. Material carried by rivers from high places fills depressions earth's crust. The Amazonian, Orinokskaya, Laplatskaya lowlands are vast flat plains composed of river sediments.
The river network of North America has a similar structure. Here, the areas of endorheic regions are also small. Many rivers carry water to the Atlantic Ocean and the Gulf of Mexico. The largest of these is the Mississippi system, which collects water from the Cordillera, the Appalachians, and the American plains (8.3). Stormy rivers flow into the Pacific Ocean, cutting through the Cordillera. The Mackenzie River, which has an extensive network of tributaries, flows into the Arctic Ocean. Short full-flowing rapids flow into the Hudson Bay.
