Since South America receives as much precipitation as does not fall on any other continent in the world, a huge number of rivers have formed here. The most full-flowing river of our planet is located here for this very reason. The Amazon is entirely inequatorial beltSouth America. And thanks to its huge area on the mainland, it collects as much water from its pool as no other river on Earth. The Amazon is more than ahead of the most full-flowing river in the Eastern Hemisphere, the Congo, in terms of the amount of water. The water flow in the lower reaches of the Amazon reaches 220 thousand m3 / s. If you measure the length of this river not from the confluence of the Maranyon and Ucayali, but from the source of the Ucayali in the Andes, then the Amazon will also become the longest river on the planet. When it flows into the Atlantic Ocean, the Amazon forms the largest delta in the world. The river remains full-flowing all year, although the water level changes somewhat, this is due to the floods of the tributaries feeding the Amazon. Many tributaries of the Amazon have their sources already insubequatorial climatebelt. However, the left tributaries belong to the Northern, and the right - to the Southern hemispheres, because their spills alternate. With the arrival of the rainy season to the north by June-August, the left tributaries are filled with water, and in December-February, the rainy season comes already to the Southern Hemisphere, since now the wetequatorial airmassfollowing the onset of summer. The tributaries carry a huge amount of water into the Amazon, it is replenished from falling rains and from melting glaciers. Interesting is the place where the Rio Negro flows into the Amazon. Rio Negro got its name from the dark color of the water. At the confluence with the Amazon, the water from it does not mix for several more kilometers and continues to flow in the form of a separate dark stream (in the Photo).

Another very large river of the mainland is the Parana River. Its source is located on the Brazilian plateau, it itself flows south through the subequatorial, tropical and subtropical belts of the mainland, flowing into the Gulf of La Plata. The flooding of the river is also associated with the rainy season and the melting of the glaciers in the Andes, which feed its many tributaries. Therefore, the Parana flood occurs in the summer months of the Southern Hemisphere - December-February. In contrast to it, another river flows in the north of South America - the Orinoco. Despite the fact that its flood is also dated for the summer, due to its location in the Northern Hemisphere, it floods in June-August.
A feature of the location of the rivers of South America is that all major rivers belong to the Atlantic Ocean basin. This is due to the fact that the watershed of the Atlantic and the Pacific Ocean passes through the Andes, which are located near the Pacific coast itself. For this reason, the formation of large rivers flowing into the Pacific Ocean is impossible.

There are few lakes in South America. There are no very large lakes here. The largest lakes are Titicaca and Maracaibo. Titicaca is the highest navigable lake in the world. The water in it is always quite cold due to the fact that it is located at a high altitude. The Desaguadero River connects Titicaca with another, also high-altitude, endorheic Lake Poopo. Lake Maracaibo (pictured) is located in the north of the mainland, it is connected by a narrow and shallow strait to the Gulf of Venezuela and the Caribbean Sea, however, it is considered a lake. This is the largest lake in South America. Its name translates as "Land of Mar" - the local leader during the colonization of the mainland. Now the lake plays a very important role in the economy of Venezuela, as huge volumes of oil are produced here, which remains the most important source of income for this country. There are a large number of oil settlements on the shores of the lake. The real miracle of the nature of these places are the "lightning Catatumbo". In the place where the Catatumbo River flows into Lake Maracaibo, lightning strikes 1.2-1.6 million times a year, that is, from 140 to 160 days a year, almost continuously for 7-10 hours per night. This unique natural phenomenon to this day is a real beacon of Lake Maracaibo, serving for all ships, because lightning can be seen from 400 kilometers away! The phenomenon is explained by the collision of air currents from the Andes with rising methane from local swamps, which forms a strong potential difference on the clouds, constantly discharging in the form of celestial electricity.

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Inland waters of South America

Introduction

The features of the relief and climate of South America predetermined its exceptional wealth of surface and ground waters, the enormous amount of flow, the presence of the deepest river in the world - the Amazon. Occupying 12% of the land area of ​​the Earth, South America receives about 2 times more (1643 mm) of the average amount of precipitation per unit of the entire area. The total river runoff is 27% of the total runoff of the Earth, the average runoff layer (58 cm) is also almost 2 times the average value for the entire land. But the magnitude of the runoff fluctuates sharply over the territory of the mainland - from a few mm to hundreds of cm. The rivers between the ocean basins are also extremely unevenly distributed: the Pacific Ocean basin is 12 times smaller than the Atlantic basin (the watershed between them runs mainly along the Andes ridges); in addition, about 10% of the territory of South Africa belongs to the area of ​​internal drainage, which crosses the mainland from the Gulf of Guayaquil through the Central Andean Highlands to the southern Pampas. Rain-fed rivers predominate, in the extreme south - also snow-glacial.

The layer of average annual runoff of 150–400 cm (up to 90% of precipitation) reaches its greatest value in southern Chile, which is explained not only by the abundance of precipitation, but also by the steepness of the slopes, low evaporation, and ice reserves in the upper reaches of the rivers, which cause summer floods, including including the "transit" rivers of Patagonia; the share of underground feeding of the rivers of the South Andes is no more than 20--25%. The runoff is just as great (for some rivers even up to 800 cm) in western Colombia, but rainfall and summer-autumn flash floods predominate there; underground runoff increases up to 40%. The runoff characteristics of the Amazon are similar, decreasing in its central and southern parts to 40–60 cm. The regime of large rivers, like the Amazon itself, depends on the rainy season in the upper and middle reaches of its tributaries. On the well and more or less evenly moistened outskirts of the Brazilian and Guiana plateaus, the average annual runoff is also 40–60 cm (in some places up to 150 cm) with a share of underground runoff up to 50%. In the interior regions of the Brazilian Plateau, the runoff decreases (up to 5 cm in the northeast) and becomes extremely uneven: violent summer floods are replaced by a sharp decrease in water discharge in winter, up to the drying up of small streams. The flow regime is similar in the flat areas of the subequatorial and tropical belts with rain-fed rivers (Llanos-Orinoco, Beni Mamore, Gran Chaco plains). A pronounced seasonality in precipitation leads to variability in runoff (the average runoff decreases from 50–80 to 15–20 cm) and river regimes: in the winter of the corresponding hemisphere, runoff stops in places and even large watercourses (Rio Bermejo, Rio Salado, etc. .) are divided into separate stretches with saline waters, while in summer floods flood vast areas; The flow regulators of the rivers of Paraguay and Parana are the swamp-lake lowlands of the Pantanal and the Laplat lowland. The smallest runoff (3–5 mm) is confined to the desert tropical west of South Africa, where even melted snow water from the highlands accumulates in foothill plumes and tectonic depressions, increasing the share of underground feeding of episodic rivers to 50% (only the Loa River has a constant flow into the ocean).

A large amount of precipitation brought from the Atlantic, vast plateaus that gently slope to the huge lowlands and plains that collect runoff from the adjacent slopes of the Andes, contributed to the formation of large river systems in the extra-Andean East of South Africa: the Amazon, Orinoco, Parana, and Paraguay. Uruguay; in the Andes, the largest is the river system. Magdalena, flowing in the longitudinal depression of the humid Northern Andes. Only lowland rivers are suitable for navigation. The mountain rivers of the Andes and plateaus, replete with rapids and waterfalls (Angel, 1054 m, Kaieteur, 226 m, Iguazu, 72 m, etc.), as well as full-flowing watercourses of constantly wet plains, have a huge hydropower potential (over 300 million kW).

Large lakes, mainly of glacial origin (end basins), are concentrated mainly in the Patagonian Andes (Lago Argentino, Buenos Aires, and others) and in southern Central Chile (Lianquihue and others). In the Central Andes lies the highest of the large lakes of the Earth - Titpkaka, there are also many residual lakes (Poopo and others) and large solonchaks; the latter are also typical of the depressions between the Pampina sierras (Salinas Grandes and others). Large lagoon lakes are located in the north (Maracaibo) and in the southeast of South Asia (Patus and Lagoa Mirin).

The largest rivers in South America

Amazon river

The largest river in South America is the Amazon. Most of its basin lies south of the equator. The area of ​​this most extensive river basin in the world is over 7 million km 2, the length of the river from the main source (the Marañon River) is 6400 km. If, however, Ucayali and Apurimac are taken as the source of the Amazon, then its length reaches 7194 km, which exceeds the length of the Nile. The flow of water in the Amazon is several times higher than the flow of all the largest rivers in the world. It is equal to an average of 220 thousand m 3 / s (the maximum flow rate can exceed 300 thousand m 3 / s). The average annual flow of the Amazon in the lower reaches (7000 km 3) makes up most of the flow of all of South America and 15% of the flow of all the rivers of the Earth!

The main source of the Amazon - the Marañon River - begins in the Andes at an altitude of 4840 m. Only after confluence with the first major tributary - Ucayali - within the plain, the river receives the name Amazon.

The Amazon collects its numerous tributaries (more than 500) from the slopes of the Andes, the Brazilian and Guiana highlands. Many of them are over 1500 km long. The most numerous and largest tributaries of the Amazon are the rivers of the southern hemisphere. The largest left tributary is the Rio Negro (2300 km), the largest right and largest tributary of the Amazon is the Madeira (3200 km).

Part of the tributaries, eroding clayey rocks, carry very muddy water ("white" rivers), others, with clear water, dark from dissolved organic substances ("black" rivers). After falling into the Amazon Rio Negro (Black River), light and dark waters flow in parallel, without mixing, for about 20-30 km, which is clearly visible on satellite images. south america river waterfall

The width of the Amazon channel after the confluence of Maranyon and Ucayali is 1-2 km, but downstream it increases rapidly. At Manaus (1690 km from the mouth) it already reaches 5 km, in the lower reaches it expands to 20 km, and at the mouth the width of the main channel of the Amazon, together with numerous islands, reaches 80 km during the flood. In the western part of the lowland, the Amazon flows almost at the level of the banks, in fact, without a formed valley. To the east, the river forms a deeply incised valley which contrasts sharply with the watershed.

The Amazon Delta begins about 350 km from the Atlantic Ocean. Despite its ancient age, it did not move into the ocean beyond the boundaries of the native shores. Although the river carries out huge masses of solid material (an average of 1 billion tons per year), the process of delta growth is hindered by the activity of the tides, the influence of currents, and the lowering of the coast.

In the lower reaches of the Amazon, tides have a great influence on its regime and the formation of its coasts. The tidal wave penetrates more than 1000 km upstream, in the lower reaches its wall reaches a height of 1.5-5 m. The wave rushes against the current at great speed, causing strong excitement on sandbars and banks, destroying the coast. Among the local population, this phenomenon is known under the name of "pororoka" and "amazunu".

The Amazon is full of water throughout the year. Twice a year the water level in the river rises to a considerable height. These maxima are associated with rainy periods in the northern and southern hemispheres. The greatest flow in the Amazon occurs after the rainy season in the southern hemisphere (in May), when the bulk of the water is carried by its right tributaries. The river overflows its banks and in the middle reaches fills a huge territory, creating a kind of giant inland lake. The water level rises by 12-15m, and in the Manaus region, the width of the river can reach 35 km. Then comes a period of gradual decrease in water flow, the river enters the banks. The lowest water level in the river is in August and September, then there is a second maximum associated with the summer rains of the northern hemisphere. On the Amazon, it appears with some delay, around November. The November maximum is significantly inferior to the May one. In the lower reaches of the river, two maxima gradually merge into one.

From the mouth to the city of Manaus, the Amazon is accessible to large ships. Vessels with a fairly deep draft can penetrate even as far as Iquitos (Peru). But in the lower reaches, due to the tides, the abundance of sediment and islands, navigation is difficult. Deeper and more accessible to ocean-going ships is the southern arm, Para, which has a common mouth with the Tocantins River. On it stands a large ocean port of Brazil - Belen. But this branch of the Amazon is now connected with the main channel only by small channels. The Amazon with tributaries is a system of waterways with a total length of up to 25 thousand km. The transport value of the river is great. For a long time, it was the only route connecting the interior of the Amazonian lowland with the Atlantic coast.

The rivers of the Amazon basin have large reserves of water energy. Many tributaries of the Amazon, when entering the lowlands, cross the steep edges of the Brazilian and Guiana highlands, forming large waterfalls. But these water resources are still very poorly used.

Parana and Uruguay rivers

The second largest river system in South America includes the Parana River with Paraguay and Uruguay, which have a common mouth. The system got its name (La Platskaya) from the eponymous giant estuary of Parana and Uruguay, reaching 320 km in length and 220 km in width at the mouth. The basin area of ​​the entire system is more than 4 million km 2, and the length of the Parana, according to various sources, ranges from 3300 to 4700 km. The sources of Parana - Rio Grande and Paranaiba - are located in the Brazilian Highlands. Many other rivers of the system also begin there. All of them in the upper reaches are full of rapids and form several large waterfalls. The largest waterfalls are Guaira 40 m high and 4800 m wide on the Paran and Iguazu 72 m high on its tributary of the same name. They have a network of hydroelectric stations.

In the lower course of the Paraná is a typical lowland river. The main discharge maximum occurs in May due to summer rains in the Brazilian Highlands. The navigable value of the rivers of the La Plata system and La Plata itself is very high.

Orinoco river

The third largest river in South America is the Orinoco. Its length is 2730 km, the basin area is over 1 million km2. The Orinoco originates in the Guiana Highlands. Its source was discovered and investigated by a French expedition only in 1954. The Casiquiare Orinoco River connects with the Rio Negro, a tributary of the Amazon, where part of the water of the upper Orinoco flows. This is one of the most significant examples of river bifurcation on Earth. When it flows into the Atlantic Ocean, the river forms a large delta, the length of which reaches 200 km.

The water level in the Orinoco depends entirely on the rainfall that falls in the northern part of its basin in the summer (from May to September). The maximum for Orinoco, falling on September-October, is expressed very sharply. The difference between summer and winter water levels reaches 15 m.

There are few lakes in South America. The main genetic groups of lakes on the mainland are tectonic, glacial, volcanic, and lagoonal. There are small glacial and volcanic lakes in different parts of the Andes. The largest glacial and glacial-tectonic lakes are concentrated in the west of the Southern Andes.

The largest lake on the mainland - Titicaca - is located on the Andean plateau at an altitude of more than 3800 m, on the border between Peru and Bolivia. Its area is 8300 km 2, and the maximum depth is 281 m. Terraces are pronounced on the shores of the lake, indicating a repeated decrease in its level. The lake has a drain into another, shallower tectonic lake - Poopo. The water in Lake Titicaca is fresh, while in Poopó it is highly saline.

On the internal plateaus of the Andes and on the plain of the Gran Chaco, there are many lakes of tectonic origin, shallow, endorheic and saline. In addition, saline marshes and salt marshes (“salares”) are common.

Along the low-lying shores of the Atlantic Ocean and the Caribbean Sea there are large lagoon lakes. The largest of these lagoons is located in the north, in a vast depression between the Andes ranges. It is called Maracaibo and is connected to the Gulf of Venezuela. The area of ​​this lagoon is 16.3 thousand km 2, the length is 220 km. The water in the lagoon is almost fresh, but during high tides, its salinity increases markedly.

The lagoons, which have almost lost contact with the Atlantic Ocean, are located in the southeast of the mainland. The largest of them are Patus and Lagoa Mirin.

A significant part of the continent, especially the Out-Andean East, has large reserves of groundwater. In the sandy strata, syneclises are not only in the Amazon, but also in the Guiana lowland, Llanos-Orinoco, Gran Chaco, Pampa, and also in other areas, up to 40-50% of the runoff falls on groundwater.

waterfalls

Angel Falls (Angel) or Salto Angel (Salto Angel) - the world's highest free-falling waterfall with a height of 978 meters.

Angel Falls is located in the highlands of Guyana, one of the five topographic regions of Venezuela, in South America. It is located on the Carrao River. The Carrao River is a tributary of the Caroni River which eventually flows into the Orinoco. It is not easy to get to the waterfall, as it is located in a dense tropical forest. There are no roads leading to the falls.

Angel Falls falls from the top of a flat mountain, called "tepui" by the natives. A flat mountain called Auyan Tepuy (Devil's Mountain) is one of more than a hundred like it, scattered in the Guiana Highlands in southeastern Venezuela. These dormant giants are characterized by their massive heights soaring into the sky, with flat tops and completely vertical slopes. Tepui, also called "table mountains" (which accurately describes their shape), formed from sandstone billions of years ago. Their vertical slopes are continuously destroyed under the influence of heavy rains falling on the Guiana Highlands.

The natives of Venezuela have known about "Salto Angel" since time immemorial. The waterfall was originally discovered in 1910 by a Spanish explorer named Ernesto Sanchez La Cruz. However, it was not known to the world until the official discovery by the American pilot and gold digger James Crawford Angel, after whom he was named. Angel was born in Springfield, Missouri in 1899.

This enterprising experienced pilot flew over the area in 1935 and landed on the top of a lonely mountain in search of gold. His monoplane "Flamingo" got stuck in the swampy jungle at the top, and he noticed a rather impressive waterfall extending thousands of feet down. He didn't have much luck with the 11-mile hike back to civilization, and his plane was left chained to the mountain, a rusting monument to his discovery. Soon the whole world learned about the waterfall, which became known as Angel Falls, in honor of the pilot who discovered it.

Jimmy Angel's plane remained in the jungle for 33 years before being picked up by helicopter. It is currently housed in the Aviation Museum in Maracay. The one you can now see on top of the tepui is a replica of it.

The official height of the waterfall was determined by the expedition of the National Geographic Society in 1949. The waterfall is the main attraction of Venezuela.

Iguazu Falls is a wonder of the world, consisting of 275 different cascades of water, the total area of ​​​​which is 2700 square meters, and the fall height reaches 82 meters! The width of the waterfall is about 3 km. The largest waterfall is Devil's Throat, a U-shaped cliff 150 meters wide and 700 meters long, marking the border between the countries of Argentina and Brazil. The name "Iguazu" comes from the Guarani words for "water" and "big".

Many islands separate the waterfalls from each other. Approximately 900 meters out of a total width of 3 km. not covered with water. About 2 km. bridges connecting the islands help to better see all the streams. Most of the waterfalls are located within the territory of Argentina, but from Brazil there is a good view of the "Devil's Throat".

Iguazu Falls are considered the largest in the world in terms of the number of falls. During the rainy season in November - March, the water flow rate can reach 750 cubic meters per second. The roar from falling water creates an impressive roar that can be heard even several kilometers away.

Smaller waterfalls are formed by ledges of solid rock, turning the water falling on them into clouds of mist and spray. Sunlight adds the finishing touch, creating iridescent rainbows. Below, in the midst of the water, miraculously rose an island covered with trees. On one side of the island, where the water flows calmly, there is a beach with yellowish sand.

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South America, exceeding in area only Antarctica and Australia, in terms of total runoff (7500 km 3) surpasses all other continents except Eurasia, and in terms of the average thickness of the runoff layer (417 mm) it ranks first on Earth.

The formation of a dense, well-developed river network of South America is favored by climatic conditions, the history of development and the relief of the mainland. Most of South America has been dry land since the Mesozoic. This determines the antiquity of the water network in a significant part of the mainland. The relief of South America is characterized by large contrasts in heights and the proximity of the greatest lowland plains to high mountain ranges, which creates favorable conditions for the formation of large and complex river systems.

The main watershed of the mainland is located in the Andes, but does not always coincide with the highest ranges. Most of the runoff from the mainland is directed to the Atlantic Ocean, where the largest rivers of South America flow. Only relatively small streams originating in the western part of the Andes belong to the Pacific Ocean basin.

The main source of food for the rivers of South America is rainfall. Glacial nutrition is only significant in the south of the Andes; the role of snow is negligible.

Due to the limited distribution of arid territories in South America, areas devoid of peripheral runoff occupy only a small part of its surface. These are the southern regions of the Gran Chaco, the inner plateaus of the Andes, the Atacama depression and the central sections of the Pacific coast.

The hydrological regime of most of the rivers of South America is determined by the amount of rainfall and the pronounced seasonality of their precipitation. Only the equatorial regions and the extreme southwest are characterized by a regime determined by uniform precipitation.

The largest river in South America is the Amazon. Most of its basin lies south of the equator. The area of ​​the river basin is over 7 million km2, its length from the main source is 6400 km. The flow of water in the Amazon is several times higher than the flow of all the largest rivers in the world. It is equal to an average of 220 thousand m 3 / s. The average annual flow of the Amazon in the lower reaches (7000 km 3) makes up most of the flow of all of South America and 15% of the flow of all the rivers of the Earth.

The main source of the Amazon - the Marañon River - begins in the Andes at an altitude of 4840 m. Only after confluence with the first major tributary - Ucayali - within the plain, the river receives the name Amazon.

The Amazon collects its numerous tributaries (more than 500) from the slopes of the Andes, the Brazilian and Guiana highlands. Many of them are over 1500 km long. The most numerous and largest tributaries of the Amazon are the rivers of the southern hemisphere. Its largest left tributary is the Rio Negro (2300 km), the largest right and generally the largest tributary of the Amazon is Madeira (3200 km).

Some of the tributaries, eroding clay rocks, have very turbid water (“white” rivers), others have clear water, dark from dissolved organic substances (“black” rivers).

The width of the Amazon channel after the confluence of Maranyon and Ucayali is 1-2 km, but downstream it increases rapidly. At Manaus, it already reaches 5 km, in the lower reaches it expands to 20 km, and at the mouth the width of the main channel of the Amazon, together with numerous islands, reaches 80 km during the flood. In the western part of the lowland, the Amazon flows almost at the level of the banks, in fact, without a formed valley. To the east, the river valley cuts deep into the surface and presents a sharp contrast with the watershed spaces.

The Amazon Delta begins about 350 km from the Atlantic Ocean. Despite its ancient age, it did not move into the ocean beyond the boundaries of the native shores. Although the river carries out huge masses of solid material (an average of 1 billion tons per year), the process of delta growth is hindered by the activity of the tides, the influence of currents, and the lowering of the coast.

In the lower reaches of the Amazon, ebbs and flows have a great influence on its regime and the formation of coasts. A tidal wave penetrates more than 1000 km upstream, moving in the lower reaches with a wall 1.5–5 m high. heavy waves on sandbars and banks and destroying the coast. Among the local population, this phenomenon is known under the name of "pororoka" and "amazunu".

The Amazon is full of water throughout the year. Twice a year the water level in the river rises to a considerable height. These maxima are associated with rainy periods in the northern and southern hemispheres. The greatest flow in the Amazon occurs after the rainy season in the southern hemisphere (in May), when the bulk of the water is carried by its right tributaries. The river overflows its banks and in the middle course floods a vast territory, creating, as it were, a gigantic inland lake. Then comes a period of gradual decrease in water flow, the river enters the banks. The lowest water level in the river is in August and September, then the second maximum occurs, associated with the period of summer rains in the northern hemisphere. On the Amazon, it appears with some delay, around November. This November maximum is significantly inferior to the May one. In the lower reaches of the river, two maxima gradually merge into one.

As far as the city of Manaus, the Amazon is accessible to large ships. Vessels with a fairly deep draft can penetrate even as far as Iquitos (Peru). But in the lower reaches, due to the tides, the abundance of sediment and islands, navigation is difficult. Deeper and more accessible to ocean-going vessels is the southern branch - Rio Para, which has a common mouth with the Tocantins River. On it stands a large ocean port of Brazil - Belen. But this branch of the Amazon is now connected with the main channel only by small channels. The Amazon with tributaries is a system of internal communications with a total length of up to 25 thousand km.

The transport value of the river is great. In some areas, for a long time it was the only route connecting the interior of the Amazonian lowland with the Atlantic coast.

The rivers of the Amazon basin have large reserves of water energy. Many tributaries of the Amazon, when entering the lowlands, cross the steep edges of the Brazilian and Guiana highlands, forming large waterfalls. The most grandiose of them is the San Antonio Falls on the Madeira River. But these water resources are still very poorly used.

The second largest river system in South America includes the Parana River with Paraguay and Uruguay, which has a common mouth with the Parana. The system got its name (La Platskaya) from the eponymous giant estuary of Parana and Uruguay, reaching 320 km in length and 220 km in width at the mouth. The basin area of ​​the entire system is more than 4 million km 2, and the length of the Parana, according to various sources, is from 3300 to 4700 km.

The sources of Parana - Rio Grande and Paranaiba - lie on the Brazilian Highlands. Many other rivers of the system also begin there. All of them in the upper reaches are full of rapids and form several large waterfalls. The largest waterfalls are Seti-Kedas (Guaira) on the Paran and Iguazu 72 m high on its tributary of the same name. They have a network of hydroelectric stations.

In the lower reaches of the Parana - a typical lowland river. The main discharge maximum occurs in May due to summer rains in the Brazilian Highlands. The navigable value of the rivers of the La Plata system and La Plata itself is very great.

The third largest river in South America is the Orinoco. Its length is 2730 km, the basin area is over 1 million km2. The Orinoco originates in the Guiana Highlands. Its source was discovered and investigated by a French expedition only in 1954.

The Casiquiare River connects the Orinoco with the Rio Herpy, a tributary of the Amazon, where part of the water of the upper Orinoco flows. This is one of the most significant examples of river bifurcation on Earth.

When it flows into the Atlantic Ocean, the river forms a large delta, the length of which reaches 200 km.

The water level in the Orinoco depends entirely on the rainfall that falls in the northern part of its basin in the summer (from May to September). The maximum advancing on the Orinoco in September - October is expressed very sharply. The difference between summer and winter water levels reaches 15 m.

There are few lakes in South America. The main genetic groups of lakes on the mainland are tectonic, glacial, volcanic, lagoonal. There are small glacial and volcanic lakes in different parts of the Andes. The largest glacial and glacial-tectonic lakes are concentrated in the west of the Southern Andes.

The largest lake on the mainland - Titicaca - is located on the Andean plateau at an altitude of more than 3800 m, on the border between Peru and Bolivia. Its area is 8300 km 2, and the maximum depth is 304 m. Terraces are pronounced on the shores of the lake, indicating a repeated decrease in its level. The lake has a drain into another, shallower tectonic lake - Poopo. In this regard, the water in Lake Titicaca is fresh, and in Poopó it is highly saline.

On the internal plateaus of the Andes and on the plain of the Gran Chaco, there are many lakes of tectonic origin, shallow drainless and saline. In addition, saline marshes and salt marshes (salares) are common.

Along the low-lying shores of the Atlantic Ocean and the Caribbean Sea there are large lagoon lakes. The largest of these lagoons is located in the 1st north, in a vast depression between the ridges of the Andes. It is called Maracaibo and is connected to the Gulf of Venezuela. The area of ​​this lagoon is 16.3 km 2, the length is 220 km. The water in the lagoon is almost fresh, during high tides, however, its salinity increases markedly.

The lagoons, which have almost lost contact with the Atlantic Ocean, are located in the southeast of the mainland. The largest of them are Patus and Lagoa Mirin.

Inland waters of South America

Rivers.

Features of the configuration, horizontal division, relief and climate of South America are favorable for the formation of large river systems. South America accounts for 20% (7450 ​​km3/year) of the total runoff of all the land rivers of the globe, and in terms of runoff layer (414 mm) it ranks first. In the widest part of the mainland is the vast equatorial lowland of the Amazon and the gentle slope of the Brazilian Highlands. High mountain ranges stretch only in the extreme west of the continent. These features determine the extremely uneven distribution of runoff between the basins of the Pacific and Atlantic oceans. To the east, to the Atlantic Ocean, vast, usually well-moistened lowlands and plains open up, into which runoff from neighboring highlands is directed. The total area of ​​runoff to the Atlantic is 15,646,000 km2. The Andean East also includes the most powerful Amazon river system in the world. Not a single large river flows into the Pacific Ocean, and the flow into it is carried out from an area almost 12 times smaller - from 1344 thousand km2 The Andes serve as the main interoceanic watershed. More abundant moisture on the eastern slopes of the Northern Andes determines the confinement of the watershed here to the Western Cordillera. In the Central Andes, due to the aridity and isolation of the inter-Andean highlands, the Pacific Ocean basin is separated from the Atlantic basin by a vast area of ​​internal flow. In the Subtropical Andes, the drainless region wedges out and the interoceanic divide again runs along the Main Cordillera. In the Patagonian Andes, the western slopes are especially abundantly irrigated, as a result of which (as well as the history of development and geomorphological features) the line of the main watershed moves east, to the moraine ridges in the Patagonian foothills, and thus the flow of a number of areas of western Patagonia belongs to the Pacific Ocean. These main hydrographic factors, features of lithology, soils and vegetation also determine the size of the annual runoff in various regions of South America. The runoff is greatest (layer height above 150 cm) in the Andes of southern Chile, where excessive moisture in a cool oceanic climate is combined with steep slopes composed of dense crystalline rocks, with the same amount of precipitation, greater evaporation, increased transpiration of dense vegetation and low water loss weathering crusts reduce the annual runoff from the coastal slopes of the Guiana Highlands and the Andes of Colombia to 80-120 cm. The same reasons reduce the runoff of the eastern slope of the Brazilian Highlands to 40-80 cm and Western Amazonia to 60-90 cm.

In the latter, in addition, the flatness of its surface contributes to a decrease in runoff. In other areas of the equatorial-tropical east, due to high evaporation and less precipitation, the runoff decreases to 40-60 cm. In the Gran Chaco (wet-arid climate with insufficient moisture) and in the northeast of the Brazilian Highlands extremely poor moisture) the runoff drops to 10–20 cm, and even to 1–2 cm. water loss of loess-like and clay soils, as well as high evaporation and significant transpiration of natural and cultivated grass cover. The least favorable runoff conditions are found in the desert Pacific slopes and the closed basin highlands of the tropical Andes, the Precordillera depressions and the semi-desert plateaus of Patagonia (less than 5 cm, in Atacama up to 10-15 mm). In fact, almost all of these areas have only periodic surface runoff and no runoff to the ocean. Inland runoff areas in South America account for 5.5% of the area. They form an elongated belt from the Gulf of Guayaquil to the southern Pampas, crossing the Andes at 24-29 ° S. sh. Most of the rivers in South America are predominantly rain fed. On the interior plains, the rain supply is supplemented by ground water, which predominates near rivers in the western desert part of the Central Andes. Snow nutrition plays a significant role only near the rivers of western and southern Patagonia, and glacial nutrition plays a significant role in the southern Andes, especially in the extreme southwest. However, in each specific case, rivers (for example, in the middle of Chile) can have different sources of nutrition in separate areas, which determine their very complex regime. Most South American rivers belong to the equatorial and subequatorial tropical type of regime. Many tributaries of the upper Amazon belong to the equatorial type. They are characterized by rain feeding, high water flow and relatively uniform flow throughout the year. Amazon has a more complex mode. The Amazonian lowland collects runoff from all the main elevations of South America surrounding it and lies between 3 ° N. latitude and 5°S sh., i.e., in a richly moistened area. This explains why the Amazon is the most full-flowing river in the world (the average flow at the mouth is 120 thousand m3/s, the maximum is about 200 thousand m3/s, the minimum is 63 thousand m3/s, the annual flow is 3160 km3) with the most extensive basin - 7050 thousand km2

In length, if the Marañon River is taken as the source, the Amazon (5500 km) is inferior to the Nile and the Mississippi-Missouri. But if we take the Ucayali River (2652 km) as the source, then the length of the Amazon (6573 km) is almost equal to the Nile (6671 km). Unlike the latter, the Amazon has many full-flowing tributaries; 17 of them have a length of 1500 to 3500 km, more than a hundred tributaries are navigable. Fluctuations in the flow of the Amazon depend mainly on the regime of its huge subequatorial and tropical tributaries, especially the longer right tributaries, originating at 20 ° S. The highest level in the middle reaches (ascent by 12-15 m) is reached by its waters in May-June, when the flood runoff from the Brazilian Highlands has time to reach, the rainy period is established in the basin of the left tributaries, and melted snow waters begin to flow from the Northern Andes. Spills spread over tens and even hundreds of kilometers wide (the width of the channel at Manaus in low water is 5 km). The powerful hydropower resources of the Amazon system are almost not used, and the rivers of the basin are only transport routes. The large tributaries of the Amazon and most of the rivers in the north and east of South America (Magdalena, Orinoco, Parana-Paraguay, San Francisco, etc.) belong to the subequatorial-tropical type. They are fed mainly by seasonal (mostly summer) rains, with which it is connected. their extremely uneven consumption (stormy summer floods and a sharp winter decline). The largest of these rivers and the second in South America in terms of length (4400 km) and basin area (4250 thousand km2) - the Parana River has the most complex regime. The summer rise in the upper reaches is replaced by the autumn one in the lower reaches due to cyclonic rains in the subtropics and stagnation of flood waters in the Paraguay depression. how precipitation falls there evenly throughout the year. The late spring and summer maximums, due to the melting of snow and glaciers in the Andes, are characteristic of the rivers of Patagonia and subtropical Chile, in addition, in the latter there is an increase from winter rains. The rivers of the northern and southern outskirts of the Pacific Basin have a relatively uniform flow with high full flow, and, on the contrary, the rivers of the desert West have a periodic or even episodic flow. The hydropower resources of South America are very significant - approximately 55 million kWh. This is due to the high fullness of many rivers, the steep fall in the Andes and the highlands, the abundance of rapids and waterfalls (including the famous Iguazu Falls, with a total height of about 80 m). However, so far, hydro resources are used poorly.

Lakes.

South America is rich in large lakes only in the southern part of Ayads, where the terminal glacial lakes (Nahuel Huapi, Buenos Aires, etc.) are located. In the Central Andes, in a tectonic depression, lies the highest of the large lakes of the world - Lake Titicaca (height -3812 m, depth up to 270 m, area - 8300 km2), connected by the Desaguadero River with the lower and shallower residual lake Poopo. A number of relict lakes in various stages of bogging and salinization, as well as huge solonchaks (for example, Uyuni, Salinas Grandes, etc.), are also found in other regions of the Central Andes and in the Precordillera region. Floodplain lakes, oxbow lakes in the valleys of large rivers and lagoon lakes are widespread on the Caribbean and Atlantic coasts north of La Plata (the largest lagoon lakes are Maracaibo, Lagoa Mirin and Patus).

Bibliography

For the preparation of this work, materials from the site http://rgo.ru were used.

The purpose of the lesson: to introduce students to the features of the inland waters of South America.

Lesson objectives:

1. To acquaint students with the features of the inland waters of the mainland and their distribution throughout South America.
2. Introduce students to new terms and concepts.
3. Establish cause-and-effect relationships and work with different types of sources of geographic information.

Equipment: Maps of South America - physical, climatic (wall), computer, multimedia projector, atlas, textbook.

During the classes

1. Organizational moment.

2. Checking knowledge.

1. Name the climate-forming factors that determine the formation of the climate in South America. Explain each of these factors.

2. Prove that South America is the wettest continent. Explain the reason for this climate change. . (During the answer, use(Presentation)slide 1.)

3. Explain why in the southern part of the mainland the coasts of the Pacific and Atlantic oceans receive different amounts of precipitation.

4. Compare the role of the Andes and the Great Dividing Range in Australia in the formation of the climatic features of the continents.

5. Work with climatograms - 2 people. ( Climatograms are given to students. At the end of the survey, slides are displayed on the screen, according to which students respond.).

3. Explanation of new material.

In the last lesson, we looked at the amazing climate of South America. But this continent surprises us not only with the peculiarities of its climate, but also with water resources.

Question: Using the maps of the atlas, determine which oceans the rivers of South America flow into? Which ocean basin dominates? Why? ( Working with atlas maps.)

(The rivers of South America flow into the Pacific and Atlantic oceans. The Atlantic Ocean basin prevails due to the relief.)

The main river systems were formed on the territory of the flat east, and the rivers flowing on the Pacific coast are small and short.

Question: Determine how the relief affects inland waters?

– The nature of the flow;
– flow direction;
– the presence of waterfalls and rapids.

Question: Do you remember what are the main features of the relief of South America?

(The predominance of flat territories, but access to the surface of crystalline rocks.)

Question: How does the relief of South America affect the formation of the mainland's internal waters?

Most of the rivers in South America are flat. But even on flat rivers there are waterfalls.

Working with multimedia. Slide 4. Iguazu Falls 1”.

Due to the presence of hardly soluble rocks, waterfalls form. On the territory of the Brazilian Plateau, since the 16th century, Europeans have known the Iguazu Falls - “big water”. The height of the waterfall is 72 meters, it consists of two main cascades, and in total the waterfall includes 275 waterfalls.

The waterfall is striking in its beauty. Watch the video clip and you will understand why the Indians called the waterfall “Big Water”.

Working with multimedia. Slide 5. “Iguazu Falls 2”.

But Iguazu Falls is not the only pride of South America.

Working with multimedia. Slide 6. “Angel Falls”.

On the Guiana Plateau, in the basin of the Caroni River, there is one of the wonders of nature, the highest waterfall on Earth - Angel Falls. In the northeastern part of the plateau rises Auyan-Tepui - Devil's Mountain. Its sheer cliffs rise to a height of up to 1.5 kilometers. In 1935, the Englishman Angel went by plane to explore these wild places and, flying by, he saw a unique waterfall that appears as if from clouds. Only in 1949 was the height of the waterfall established - 1054 meters, which is 21 times higher than the famous Niagara Falls. The waterfall can only be seen from a height, at the foot of the mountain, as if a river arises from the air, carrying its waters from the ocean.

But the placement of inland waters depends on several factors, and not only on the features of the relief. Slide 7 “Rivers of South America”

Question: Name the factor on which the internal waters of the continent still depend.

Another important factor in the formation of inland waters is the climate.

Question: They say that “rivers are a mirror of the climate”, how do you understand this statement?

(The amount of precipitation and the mode of precipitation affects the characteristics of inland waters.)

Working with multimedia. Slide 8. “The largest rivers in South America.”

Task: Look at the table and identify the largest river systems in South America.

There are large river systems on the mainland. In the northern part of the mainland, the Orinoco River flows. The source of the river was found only in 1951, at the same time the length of the river was determined - 2740 km.

Question: Look carefully at the map and answer the question, what is strange and unusual in the course of the river?

Below the village of Esmiralda, the river is divided by a crystalline ledge into two parts, one of which continues to flow in the same direction, and the other, called Casiquiare, becomes a tributary of the Rio Negro. This phenomenon is called bifurcation.

A bifurcation is a bifurcation of a river, in which each of the formed branches belongs to different river systems. (Entry in a notebook.)

For 400 km from the mouth of the Orinoco it becomes navigable for ocean-going vessels, the depth of the river exceeds 30 meters. Below the Barrancas, the river is divided into a huge delta with an area of ​​\u200b\u200babout 18 thousand km².

Climatically, the Orinoco basin is divided into two seasons: rainy (April to October) and dry (November to March). During the wet season, in the lower reaches, the water rises by 15 meters, the river overflows for 10–15 km.

The second longest river system in South America is the Rio de La Plata, which means “silver river” in Spanish. So the newly discovered river was named by the Spanish conquistadors, hoping to find the precious metal. The name of the river seems like a cruel joke, because the river carries a huge amount of silt into the ocean, which makes the river muddy and opaque.

The Indians called this river Parana, which means “relative of the ocean.” In the lower reaches of the Parana, it merges with the Uruguay River and forms a huge estuary, the length of which is 320 km. The width of the estuary near the ocean is 220 km, against Monte Video - 105 km and near Buenos Aires - 40 km. Parana is navigable for more than 2000 km from the mouth for ocean-going ships and rightfully bears its name.

But the true queen of the inland waters of South America is the Amazon. The river got its name in honor of the ancient mythical Amazons. For a long time, Europeans could not penetrate deep into the Amazon and came up with a legend according to which formidable warriors guard the passage to the Amazon.

Working with multimedia. slide 9. “ Amazon and its tributaries.

“All that can be heard or read about the size of the Amazon and its tributaries does not give an idea of ​​its immensity. You have to sail on it for months to understand how much water dominates the land here, ”one of the European researchers wrote about the Amazon. In fact, there seems to be nothing more majestic and mysterious than this great river. Until now, this river has not been blocked by any bridge, dam or dam. The area of ​​the river basin is about 7.2 million km², which is only slightly inferior to the area of ​​the entire mainland of Australia.

The Amazon is often referred to as the greatest river in the world. And although in length it is slightly inferior to the Nile, but in fullness it has no equal.

Working with multimedia. Slide 10. "Amazon".

The Amazon has over 500 tributaries, including 1,500 to 3,500 km long. In low water, the width of the channel in the middle reaches is 5 km, and the depth is 50 meters. On the last 400 km stretch before flowing into the Atlantic Ocean, the width of the river is more than 50 kilometers, and the depth is more than 90 meters. At the mouth, the width of the river is already 80 kilometers. The city of Manaus is a seaport.

The source of the great river is located in the Andes at an altitude of about 4-5 thousand meters, there is a small lake Ninyokocha. Small rivers flow into it from the surrounding mountains, and a small stream flows out of it. This is one of the origins of the Amazon. But the Amazon itself appears after the Ucayali and Marañon merge into a single stream. With the exception of rapids, the Amazon and its tributaries flow slowly due to the slight slope of the river. And because of this, the Atlantic tides rise more than a thousand kilometers from the ocean. This phenomenon has been called a vice.

Pororoka (thundering wave) - the movement of a sea tidal wave in shallow water and lower reaches with a wave up to 5 meters high.

The Amazon is exceptionally full of water throughout the year, but in May-June, the highest water level is observed.

Question: What do you think is the reason for the rise in the water level in the river?

(Peculiarities of the climate and the river system: the numerous right tributaries of the Amazon flood just during this period of the year).

Working with multimedia. Slide 11. Video clip “ Amazon”.

The organic world of the Amazon is unique. Amazing Victoria Amazonian. able to withstand weight up to 50 kilograms on its leaves. The most famous fish in the Amazon are piranhas. Sharp teeth and powerful jaws allow these fish to deal with their prey very quickly. Cases have been recorded when a flock of piranhas butchered a bull within 3 minutes. The Indians used the jaws of these fish as scissors. The largest fish in the Amazon is the pirarucu. The length of the largest individuals is up to 5 meters and weighs up to 90 kilograms. The average pyraruk sold on the market weighs up to 25-30 kilograms. This is only a small part of the amazing animals and plants of the Amazon. Watch the video clip carefully and name those animals and birds that you know.

Working with multimedia. Slide 12. "Representatives of the organic world of the Amazon."

Working with multimedia. Slide 13. Video clip “ Amazonia”.

There are few lakes on the mainland.

Question: On the map of the atlas, determine the name of the lakes of South America and the origin of the lake basins.

The largest lakes are Titicaca and Maracaibo Lagoon.

Working with multimedia. Slide 43. “Lakes of South America”.

The name of Lake Titicaca translates as "lead rock". In fact, at dawn, the lake amazes with the absolute real estate of mirror waters. There was a beautiful legend according to which the Incas, in order to prevent their treasures from falling to the Spanish conquistadors, melted down all the gold they had and flooded it in the lake, which they considered to be bottomless. In the second half of the last century, Jacques Yves Cousteau organized an expedition in search of legendary treasures. Despite all efforts, the Inca treasures could not be found. The only thing the expedition achieved was to measure the depth of the "bottomless" lake - 320 meters.

4. Consolidation of the studied material.

Today we examined the features of the inland waters of South America.

At the end of the lesson, I suggest giving the correct answer without looking at the map.

1. Do most rivers belong to the Pacific or Atlantic Ocean? (Atlantic.)
2. Is the Amazon flowing east or northeast? (East.)
3. Which waterfall is further north - Angel or Iguazu? ( Angel.)
4. Is the general direction of the Paraná current south or north? (South.)
5. Is Lake Titicaca in the Andes or the Brazilian Plateau? (In the Andes.)
6. Is the Amazon Basin mostly Brazil or Peru? (Brazil.)
7. Is the Maracaibo lagoon located in Venezuela or Colombia? (Venezuela.)

5. Homework.§ 43.