Australia is the smallest continent in the world, located in the southern hemisphere. The area of Australia with its islands is less than 8 million square meters. km, population is about 23 million people.
The western and southern coasts of the continent are washed by the Indian Ocean, the northern by the Timor and Arafura Seas of the Indian Ocean, the eastern 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 South-East, in the east - Cape Byron. The distance from the extreme northern to the extreme southern points of the continent is 3200 km, from western to eastern – 4100 km. The Great Barrier Reef stretches parallel to the eastern coast for 2,300 km.
The coast of the mainland is slightly indented. There are large Gulfs of Great Australia 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 Arnhem Land. This continent includes the adjacent islands - Tasmania, Melville, Kangaroo, etc.
The continent lies on the ancient Australian platform, which passes into the East Australian fold belt. The average altitude of Australia is 215 m above sea level, with most of the continent's territory occupied by plains and up to 95% of the territory located below 600 m. In the eastern part of the continent, 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 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, and 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 predominant 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. A characteristic feature of Australia is the presence of creeks - rivers that fill with water only after heavy rains.
The vast interior spaces of the continent are home to the Great Gibson Desert, Victoria Desert, Great Sandy Desert, etc. Salt lakes can often be seen here. Around the deserts there is a belt of semi-deserts with shrubs. In the northern, eastern and southeastern regions, semi-deserts give way to savannas. In the mountainous regions and along the coasts there are forests of palm trees, tree ferns and eucalyptus trees. Among the wild animals in Australia there are large numbers of rabbits, pigs, and wild dogs. Among the 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 indigenous population makes up only 2% of the total population, the rest of the inhabitants are descendants of Europeans and Asians who colonized the mainland after its discovery in the 17th century. The high level of development of agriculture and the mining industry has brought the country to a leading position as a supplier of wheat, coal, gold, and iron ore to the world market.
K.S. LAZAREVICH
In No. 5/2006, diagrams of river systems in Russia were published. The experiment turned out to be successful: the diagrams allowed teachers to navigate the difficult (and very confusing by the authors of textbooks, who do not bother to think about the numbers) question of the “longest rivers” and “longest watercourses” in Russia or in its individual territories.
Schemes for all continents are published here, built on the same principle as schemes for Russia. The diagrams allow you to establish the lengths of rivers, compare rivers and systems with each other, and create a visual representation of river systems and sea drainage basins.
Within the diagram for each continent, the rivers are placed in the order in which their mouths are located along the coast of the World Ocean, circling the territory clockwise. Rivers that do not flow into the World Ocean are listed last, on a gray background.
Rivers - the main ones and their tributaries - are depicted by vertical lines. The flow of rivers is everywhere from bottom to top, so that the left tributaries and components of the rivers are on the left, the right ones on the right. The lengths of the rivers are given to scale, they are depicted by vertical lines, the horizontal segments are given only to show the relationships of the rivers, and have no length.
The numbers written on the diagram at the sources of the rivers and at the horizontal sections indicate the distances along the riverbed 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 diagram, the reservoirs into which the rivers flow are labeled. All signed figures are taken from reference books; It should be borne in mind that for poorly explored areas (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 distances not marked on the diagram (for example, between the mouths of tributaries), use a scale ruler. But remember that such measurements will only give an approximate result: the constructions were made by taking measurements on a map.
It is better to use the diagram 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 raise doubts are explained: unusual shapes of mouths and questions arising 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 order of their mouths along the coast of Asia, from the northern end of the Ural Mountains, skirting the continent, to the Sea of Azov. Next comes Europe - first the south, then the west and the north. At the end of the diagram are 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.
IN 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: Changjiang, Yangtzejiang), flows in the Pacific Ocean basin. The Huaihe River, which flows into it in the lower reaches, carries and deposits a lot of solid material (sand, clay), so the channel mainly lies above the adjacent plain, which is why catastrophic floods often occurred, the river flowed either into the Yangtze or into the Yellow River. After the construction of the irrigation system in the 50-60s of the twentieth century. The threat of floods has been largely eliminated, but part of the Huaihe runoff continues to flow into the Yellow River, which is reflected in the diagram.
The Mekong River, which flows into the South China Sea, is one of the longest rivers in Asia, high-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-Tibetan mountains creates a series of isolated long and narrow drainage basins.
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 indicated as 2700 km, the Brahmaputra - 2900 km; Apparently, Meghna is included in this length, based on which the diagram is constructed.
The Tigris and Euphrates rivers flowed separately into the Persian Gulf in historical times, 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 classified as Asia, since it flows south of the Kuma-Manych depression.
Europe is studied in school in more detail than other parts of the world, many geographical objects of Europe are constantly heard, so the scheme also includes small by the standards of other territories, but well-known rivers. Of the rivers in Europe, only the Volga and Danube can be compared with the largest Asian rivers, although they are significantly smaller than them.
Europe is essentially a peninsula of the Eurasian continent. Within its boundaries, Western Europe, located outside the former USSR, and Eastern Europe, located within its borders, are distinguished.
In Eastern Europe, which is 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 is one and a half to two thousand kilometers, and a river two (Dnieper, Don) or even three and a half thousand kilometers long (Volga) is not surprising.
And in long and narrow Western Europe there is no point at all more than 600 km away from the sea, and almost all rivers are short. Only the Danube, starting less than four hundred kilometers from the Mediterranean Sea and five hundred from the North, managed to travel halfway across Western Europe and reach the Black Sea almost three thousand kilometers later. Rivers south of the Danube flow into the Mediterranean Sea, and to the north into the North and Baltic. West of the source of the Danube, the watershed runs through the south of Europe - these are the Alps, the French Massif Central, the mountains of southern Spain (Cordillera Betica, Sierra Nevada), and the rivers that flow into the Mediterranean Sea are quite short, and the longer ones flow directly into the Atlantic Ocean, in Bay of Biscay and English Channel. This is why the Mediterranean Sea is somewhat saltier than the Atlantic Ocean. An exception to the rivers flowing into the Mediterranean Sea 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 traveling 928 km, flows into it.
The French rivers Garonne and Dordogne, which form the common Gironde estuary with a length of 75 km, may cause difficulties on the diagram. The length of both rivers is counted from the exit of the Gironde into the Bay of Biscay.
The diagram of the river of endorheic basins is completed. The Caspian Sea only washes the southeastern edge of Europe for a short distance, but the Caspian drainage basin 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 is dying because these rivers do not flow into it all year round - their water is taken away for irrigation; The downstream channels are shown with a broken line. The channel of the Tarim (in the upper reaches the river is called Yarkand) is very unstable, the Tarim only occasionally feeds Lake Lop Nor, and sometimes goes into other bodies of water or into the ground, so one can only talk approximately about its length.
The river network belongs to the Atlantic and Indian Ocean basins. The Nile system is located in the eastern part of the continent, very close to the Indian Ocean, but the Nile flows into the Mediterranean Sea - the 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 area, almost 400 thousand km 2), the White and Black Volta flow into it, and the Volta River begins from the reservoir dam.
North America
The rivers of North America belong to the basins of three oceans. The large Mackenzie (into the Beaufort Sea) and Nelson (into Hudson Bay) rivers flow into the Arctic Ocean. To the south, the topography of the continent determines a sharp asymmetry of the river network: the Atlantic Ocean basin is much larger than the Pacific basin. 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. There is not 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 is not included in this system and why?)
South America
The continent is washed by two oceans, and the length of the coastline of the oceans differs only slightly. However, all the rivers included in the scheme belong only to the Atlantic Ocean basin - the ocean itself or the Caribbean Sea, 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 edge of the continent. The diagram shows a bifurcation - the division of one river into two: in the upper reaches of the Orinoco, the Casiquiare River, 410 km long, is separated from it, flowing into the Rio Negro - a tributary of the Amazon; the broken arrow on the diagram shows where Casiquiare flows, but, of course, it is impossible to measure the distance using this arrow. We have already encountered 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 diagram: there is only one large river flowing into the ocean - the Murray. And is it really that big if it carries about 10 km 3 of water into the ocean per year? For comparison: Amazon - almost 7000, Lena - more than 500, Volga - 250. And there is also Coopers Creek, which only reaches Lake Eyre during heavy summer rains, otherwise it simply goes into the ground somewhere halfway.
Tasks for working with diagrams,
printed on p. 10–18
You need to give tasks to students little by little; to indicate or not to indicate in which river system the solution should be sought is at the discretion of the teacher; It is quite possible that the same teacher in one class will make 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 a river from a 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 Marañon to the source of the Ucayali (remember which river system they belong to).
There can be a lot of tasks of this type. Invite students to create several of these assignments themselves. Let them familiarize themselves with how the diagrams were compiled (the introductory part of the explanatory text for the diagrams), and answer which of the tasks you proposed and which of the ones they compiled can be solved exactly, which ones - only approximately, and why.
2. When solving each example from task 1 Note which rivers, up or down their course, you are moving from the starting point to the final point.
3. Using any cards, place cities on river diagrams.(Let the teacher suggest the list of cities himself. Considering that the next task asks to measure distances between cities, several cities should be selected in the same river system.) If students do not know where to look for these cities, have them look in the atlas's geographical names index . If the city is located on both banks of the river or you do not have information on which bank it is located, place a circle on the line indicating the river; if on one bank, then on the corresponding side of the line.
Which of these cities were you able to map exactly, and which approximately? Why?
4. Measure at least 10 distances between caused by you cities along rivers. Which of these distances were you able to measure accurately, and which approximately? Why?
5. Place a north-south arrow at each river system. Rivers are meandering, so it can only be estimated approximately, taking into account the general direction of the main river. For the Mississippi system, place (dotted) the second arrow, corresponding to the fact that the source of the Missouri is taken as the main source.
6. Mark in the diagram with a black triangle mouths of rivers with deltas. Not all deltas are visible on the map; indicate only those that are expressed in scale on physical maps of continents and parts of the world in school atlases.
In the diagram of Russian rivers (“Geography”, No. 5/2006), Lake Kubenskoye and the Kubena River flowing into it were omitted in the Northern Dvina system. If you use this diagram, add it to it, just remember that the diagrams in that issue and here are built on different scales.Rivers Eurasia carries almost half of all water flowing from the planet's land into the World Ocean. The continent surpasses all continents in terms of river flow. Of the 14 greatest rivers in the world (more than 3 thousand km long), most are located in Eurasia: Yangtze, Yellow River, Mekong, Indus, Lena, Ob, Yenisei, Volga.
Rivers are unevenly distributed across the continent. 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. In Europe, small rivers predominate. The largest rivers of Eurasia originate in the interior of the continent, high in the mountains, and spread in all directions to the outlying plains. In the upper reaches they are all mountainous, in the lower streams they are flat, calm and wide. Flowing from the mountains, the rivers lose speed, expand the valley and deposit the brought material - alluvium. The largest plains of Eurasia are alluvial.
Rivers of Eurasia extremely diverse in types of nutrition and flow regime. The same river, crossing different climatic zones, in its different sections is fed by water from different sources, 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 rivers on the outskirts of the continent with non-continental climates. Floods on different rivers occur at different times of the year, depending on the onset of the rainy season or snow melting. In rivers of continental regions, groundwater plays a major role in nutrition. During low water, some dry out completely. Rivers originating in the mountains of Europe in the center, east and southeast of Asia are fed by the waters of melting glaciers. Asian rivers flowing through permafrost also have a glacial type of feeding.
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 does not drain into the World Ocean. Accordingly, the territory of Eurasia is divided into five drainage basins. Four of them are ocean basins, and the fifth is an internal drainage basin. This is the largest internal drainage basin on the planet.
Pool Arctic Ocean occupies the northern edge of Eurasia. “Record holders” of the pool: Lena - has the longest length - 4400 km; The Ob (3650 km, with the Irtysh 5410 km) is the largest drainage area - about 3000 km 2 (Fig. 39); The 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 plains - low or high, from south to north - crossing several natural zones. A significant part of their valleys is located in the zone of perennial frost. They feed on melted snow, rain and glacial waters. In winter they freeze, and many of their small tributaries freeze to the bottom.
Rivers of the basin Pacific Ocean - Yangtze (6380 km) (Fig. 41), Yellow River (4845 km), Mekong(4500 km) (Fig. 42), Amur(2850 km) - have a monsoon type of regime and are distinguished by high water content. In summer, when the rainy season begins and the snow melts in the mountains, up to 80% of their annual flow occurs. The water level at this time rises by 20-40 m. Floods are accompanied by severe floods. At this time, rivers flood their valleys and fill them with a thick layer of loose sediment. The longest river on the continent, second only to the Nile, Amazon and Mississippi, - Yangtze. It begins in Tibet, breaks through rapids gorges onto the alluvial plain, where it flows among vast lakes and swamps. When it flows into the East China Sea, it forms a long, narrow estuary - a funnel-shaped, widened mouth. It is formed by the force of sea tides rising upstream of the river for several hundred kilometers. By the rivers of the basin Indian Ocean also monsoon regime. 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 rivers tirelessly fill them with alluvium. Its thickness in the Ganges Valley reaches 12 km. The Ganges-Brahmaputra system is third in terms of water content after the Amazon and Congo: every second 7,700 m 3 of water is carried into the ocean. 500 km from the ocean, the Ganges begins to form branches of a giant delta - the largest on the globe (with an area of more than 80 thousand km 2).
From the rivers of other basins of the rivers of the basin Atlantic Ocean are diverse. They do not form large systems, have a smaller and more uniform flow, and all possible power sources. Some of them freeze in winter, while others do not freeze up. Polomaputra (space image)
water and floods occur at different times. The largest river is 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 reaches it becomes a typically flat river - calm, with a wide floodplain and numerous oxbow lakes. The river cuts through the Carpathians through a narrow valley and, splitting into branches, flows into the Black Sea.
Pool internal drain occupies the central part of the continent. Its rivers are usually short and do not form a dense network. They feed mainly on underground waters and often do not bring water to rare lakes, getting lost in the sands of deserts.
Its main river is not at all typical for the basin 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 deep - it is fed by abundant water from melted snow and rain. To the south they dry up, but consumption increases - for evaporation and economic needs. The Volga flows into the Caspian Sea, forming a powerful delta consisting of hundreds of channels and islands.
Lakes Eurasia is numerous and diverse. They are unevenly distributed over the territory and differ in the origin of the basins, size, nutrition, temperature, and salinity.
The northern part of the continent, covered by ancient glaciation, is dotted with glacial lakes. The largest (including the largest in Europe Ladoga And Onega lakes) occupy tectonic troughs deepened by a glacier. There are also many glacial lakes in the mountains of Central Asia and the Himalayas. Common in southern Europe, western and southeastern Asia karst lakes. The Far East and the Japanese Islands are rich volcanic lakes. Common in river valleys floodplain oxbow lakes. A significant part of 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 are Bodenskoe And Balaton- located in foothill deflections. Areas of continental rifts occupy the deepest lakes - Baikal (1637 m) and Dead Sea. There is a lake in a tectonic depression Issyk-Kul.
Lakes in areas with a humid climate are fresh, while those in a continental climate are salty to varying degrees. The salinity of closed lakes is especially high.
The surface of this endorheic lake in Arabia - the lowest place on Earth's land - is 405 m below sea level. In some years, the water level drops to –420 m, and the 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. Groundwater in Eurasia is 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. Swamps 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). Permafrost was formed during ancient glaciation. The modern climate in high latitudes contributes to its preservation (relict permafrost), and in the inland regions of the temperate zone - its formation (modern). The thickness of the 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 Eurasia, Europe and 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 continent's territory. Almost 90% of Eurasian glaciers are mountain . In Europe, the most powerful mountain glaciation is in the Alps, in Asia - in the Himalayas (30 times more extensive than the Alpine). Pokrovnoe glaciation developed on the northern islands.
In the Caucasus, Scandinavia, the Polar Urals, Taimyr, northeast Siberia, Kamchatka, and the Japanese Islands, glaciation is facilitated by the oceanic (or coastal) position of the mountains, which allows precipitation to be retained. The formation of glaciers in Central Asia - in the Pamirs, Tibet, Kunlun, Karakorum, Tien Shan - is prevented by the dryness of their continental climate, but is facilitated by the enormous altitude.
Rice. 47. Distribution of permafrost
Changes in the state of water bodies under the influence of economic activities. The enormous water wealth of the continent is intensively used in agriculture. However, due to the uneven distribution of inland waters across the territory, some regions experience an extreme lack of water resources, while others face the problem of excessive surface moisture.
The shortage of water resources is especially acute within the continent - in the internal drainage basin. Agriculture and human life here are possible only with artificial irrigation. Often, river water is completely withdrawn, depriving reservoirs of internal drainage. This causes a chain of environmental problems: soil salinization, increased wind erosion, and 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, cannot bring their waters to the Aral Sea, which because of this has turned into several small lakes.
To remove excess moisture from the swampy woodlands of Europe and the rain-waterlogged lowlands of South and Southeast Asia, drainage reclamation is carried out . Often, drainage that does not take into account the hydrological regime of biocenoses entails a chain of negative environmental consequences. The continental climate is increasing, peat bogs are being destroyed, plant and animal species are disappearing forever, small rivers and lakes are drying up, and soil erosion is increasing.
Intensive management leads to pollution of surface and groundwater with pesticides, mineral and organic waste, synthetic substances, and petroleum products. The “circulatory system” of the continent, “infected” with harmful substances, permeates the surface rocks, carries these pollutants over long distances, spreading the “infection”, and then carries it into the World Ocean. 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.
Due to global warming, one of the causes of which is human economic activity, there is rapid degradation of permafrost and intensive melting of glaciers, which leads to a gradual increase in the level of the World Ocean.
Bibliography
1. Geography grade 9 / Textbook for grade 9 institutions of general secondary education with Russian language of instruction / Edited N.V. Naumenko/ Minsk "People's Asveta" 2011
LESSON 33. LAND WATERS OF SOUTH AMERICA. LARGEST RIVER SYSTEMS
Educational goal: to familiarize with the general features of the continental land waters, the main river systems; promote understanding of the influence of climate and topography on the formation and distribution of land waters; improve skills and abilities to characterize the largest river systems of the continent.
Equipment: physical map of South America, textbooks, atlases, contour maps.
Basic concepts: land waters, river basins, river system, regime, nutrition, waterfall, tectonic lake, lagoon lake, glacier, groundwater.
Lesson type: learning new material.
II. Updating basic knowledge and skills
Complete the sentences.
South America is located in climatic zones: equatorial...
The amount of precipitation falling on the east coast is about...
The special type of climate that forms in the Andes is called...
The inland waters of the continent include: rivers...
The deepest river in the world, located in South America, is called...
III. Motivation for educational and cognitive activities
The idea is well known: “The water network of the continent is a mirror of its climate and topography.” Do you agree with him? Today in class, while studying the inland waters of South America, you have the opportunity to confirm or refute this statement.
IV. Learning new material
1. General characteristics of the inland waters of South America
South America ranks first in terms of water availability. The continent covers about 12% of the land area, but accounts for 27% of the world's total water flow. This is primarily due to the extremely humid climate. Large river systems have formed here. The vast majority of them belong to the Atlantic Ocean basin. The most powerful rivers: Amazon, Parana, San Francisco, Orinoco.
Most rivers are fed by rain; only some rivers receive water from melting snow and ice in the mountains. Flowing in the Andes, crossing the plateau, the rivers of South America form numerous rapids and waterfalls. On one of the tributaries of the Orinoco River there is the highest waterfall in the world - Angel (1054 m), and on a tributary of the Parana there is a powerful waterfall - Iguazu (72 m).
There are relatively few lakes in South America. The largest lake on the mainland is the lake-lagoon of tectonic origin Maracaibo. In the Central Andes, in a depression at an altitude of 3812 m, the largest high-altitude lake in the world, Titicaca, is located. Vast swamps form in well-moistened lowlands. Large areas of the continent are well supplied with groundwater, which is of great importance for the water supply of cities.
There are few mountain glaciers in the Andes. As you move south, the height of the snow line gradually decreases.
Student presentations with messages.
2. Largest river systems
Make a brief description of the rivers of South America according to plan. Present the results in table form:
Name |
Leak location |
Current direction |
Character of the current |
Where does it flow |
1. Amazon |
||||
3. Orinoco |
The Amazon (6516 km) is the deepest river in the world and has the largest river basin in the world (its area is equal to the area of the entire Australia). It originates in the Peruvian Andes from its main source - the Maranhoin River. After merging with the Ucayali, the river receives the name Amazon. The length of the Amazon is second only to the Nile. It contains as much water as the Congo, Mississippi, Yangtze and Ob combined. The Amazon has more than 1,100 tributaries, 20 of which range in length from 1,500 to 3,500 km. More than a hundred tributaries of the Amazon are navigable. Thanks to its numerous tributaries, the Amazon remains full of water all year round.
Other large rivers of South America - the Parana and Orinoco, unlike the Amazon, have a pronounced seasonality of flow. The maximum rise in water levels occurs in the summer season, and during the dry period they become very shallow. With the arrival of humid equatorial air, the rainy season begins, rivers overflow, flooding vast areas and turning them into swamps. Such floods are often catastrophic.
The rivers of the Parana system collect water on the Brazilian Plateau and inland plains, the Orinoco River with its tributaries - on the Guiana Plateau. In the upper reaches of these rivers there are rapids and form numerous waterfalls. In the middle and lower reaches, the Paraná and Orinoco are typical lowland rivers, convenient for navigation.
The rivers of South America have significant hydropotential; in the arid regions of the inland plains, river water is used to irrigate fields.
V. Consolidation of the studied material
What reasons explain the high river flow in South America?
To which ocean basin do most of the rivers of South America belong? What explains this?
What type of nutrition is typical for most rivers on the mainland?
What is the origin of the lakes in South America? In which areas are the largest of them located?
What do the river systems of South America and Africa have in common? What makes them different?
Why did the glaciation process in the Andes not spread significantly?
V I. Lesson summary
V II. Homework
Work through the paragraph...
Doing practical work 8 (continued). Mark the major rivers and lakes of South America on a contour map.
Advanced (for individual students): prepare reports on the natural zones of South America, individual animals and plants, changes in natural complexes by humans.
Remember the importance of water for other components of nature and for humans. What properties does water have? Which ones are geographically significant? What bodies of water are classified as land waters?
Distribution of inland waters. Water is distributed extremely unevenly across continents. There are areas where there is an abundance of rivers, lakes, extensive swamps, and in some areas there is practically no surface water, except for rare drying lakes. Of all the continents, the wettest (water-rich) is South America. If all the water flowing from this continent per year is distributed in an even layer over its area, you will get a layer of water more than 500 mm thick. This quantity is called the runoff layer (8.1). In Antarctica, almost all the water is in solid form, and does not flow into the ocean, but collapses in large blocks, forming icebergs. But in terms of volume of fresh water, Antarctica is many times greater than all continents combined. It is estimated that the reserves of fresh water contained in Antarctic ice are approximately equal to the flow of all the Earth's rivers for more than 500 years.
The distribution of inland waters across the continents most depends on climate, but other factors are also important. The distribution of rivers, lakes, swamps, glaciers, the shape of river valleys and lake basins, and the conditions of groundwater are influenced by the relief and geological structure of the area. For example, even with low rainfall, swamps can occur if the area is flat and drainage is difficult.
All types of inland waters play a huge role in nature and in human life. However, the most prominent place is occupied by rivers.
Rivers. On all continents of the Earth, except Antarctica, there are large and small river systems. South America, which receives the most precipitation, has the most extensive river network.
There are almost no areas on this continent that are devoid of rivers. The huge basins of the Amazon, Orinoco, and Parana occupy most of the continent (8.2). Most rivers originate in the mountains, cut through mountain ranges and high plateaus and plateaus, forming rapids and waterfalls. Then they emerge onto flat plains, spread widely, and turn into a dense network of water arteries. The material that rivers carry from higher places fills the depressions in the earth's crust. The Amazonian, Orinoco, and Laplata lowlands are vast flat plains composed of river sediments.
The river network of North America has a similar structure. Here the areas of drainageless areas are also small. Many rivers carry water to the Atlantic Ocean and the Gulf of Mexico. The largest of them 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 Cordilleras. The Mackenzie River, which has an extensive network of tributaries, flows into the Arctic Ocean. Short, deep, rapids rivers flow into Hudson Bay.