Rivers, large and small, flow on every continent, they not only feed lakes, seas and oceans, but also provide cities and towns with fresh water. Since ancient times, people have tried to build their settlements near water bodies. And today almost any
the capital, whether it be Moscow, Paris or Tokyo, is inextricably linked to the largest river on which it was once founded. But what is a river system, where does it originate and where does it flow?
Basic concepts
There would be no seas and lakes if they were not filled with water arteries every second, which are distributed by a network across all continents. They originate either high in the mountains or from a spring on a hill, along the way they are continuously fed by rainwater, which provide watersheds. The main river, as a rule, is large in volume of water, gives the name to the system, which is built from the tributaries flowing into it. As an example, we can cite such systems as the Yenisei or the Volga. True, the allocation of the main artery and tributaries is not always so unambiguous. Usually, for selection, attention is paid to such parameters as length, direction of flow, structure of banks, color and volumes.water. What is the river system can be understood by looking at the Amazon, its scheme is symmetrical and obvious.
Pools
The entire area of land from which the river is fed is called its basin. As a rule, it has the appearance of an ellipse or resembles a pear in shape. Its value directly has a strong influence on the economic and political life of the peoples, cities and countries living in this territory. Everyone knows that water is life, and where it is not enough, for example, in Africa, nothing can develop. That is why our wise ancestors tried to stay near the water.
If we look at the percentage of space occupied by basins separately on each continent, we can conclude that the most favorable countries in terms of hydrographic conditions are located in South (67%) and North (49%) America. Of course, because there are large river systems of the Amazon, Orinoco, Mississippi and Colorado.
Watersheds
Watersheds are conditional lines or stripes along which basins are separated from each other. The most important watershed of the planet is called the eye (A. Tillo) and separates the basin of the Arctic and Atlantic oceans, which occupies 53% of all land, and the drainage area of the Pacific and Indian oceans, they account for only 25%. This distribution is due to the structure of the earth's surface, because the shores of the last two oceans are dotted with various rises that complicate the paths of rivers, and the amount of precipitation is also of great importance. Remaining 22% landbelong to the so-called drainless region, which is characterized by the fact that the rivers flowing there have no outlet to the seas and, consequently, to the oceans. One of the largest endorheic regions is central Africa with its Sahara and Kalahari deserts. What is a river system without a watershed? The largest and most important watersheds run along the
tops of the main mountain ranges. So, for example, in America it is the Cordillera and Andes systems, for Europe it is the Alps.
Asia
The hydrography of each continent is unique and has its own characteristics. Most of the rivers in Asia originate in the Himalayas and the Tibetan Plateau, these include the Indus, Brahmaputra, Ganges, Irrawaddy, Mekong, Yangtze, Salween and Huang He. The listed rivers are the main life arteries, because they feed all the rich nature of these areas and eventually flow into warm, non-freezing seas. One more feature of Asian rivers can be distinguished, some of them can be divided into pairs, because each of the pairs originates in one place, but then they diverge to meet again at the place of flow. These are the Irtysh and the Ob, the Ganges and the Brahmaputra, the Tigris and the Euphrates, the Syr Darya and the Amu Darya. Almost every river and river system is navigable due to the fact that the territories through which they flow are represented by plains.
Europe
Water arteries here are significantly inferior to Asian ones both in length and width. The main characteristic feature can be called the close location of the sources, which ultimately leads to a star-shaped divergence of rivers, brightan example is the Valdai Upland, from which such rivers as the Volga, tributaries originate
Ilmenya, the Dnieper and the Western Dvina. By their type, most of the basins are flat, but they can be combined, since they are located near the mountains.
The Americas and Africa
But these continents account for the deepest and longest rivers. In North America, most of the water arteries are lacustrine and feed the world's largest freshwater lakes. In the Rocky Mountains of the southern mainland there is a river that gives its waters to both the Pacific and the Atlantic Ocean, it bears the name of the "two oceans" corresponding to it. As far as Africa is concerned, the scheme of the river system here is usually interrupted by a waterfall, which does not allow the development of navigation, but this applies only to the lower reaches. But in the north of the mainland, famous rivers flow, such as the Nile, Niger and Congo. They are characterized by the absence of a watershed, which leads to their confluence in the upper reaches. So we examined what the river system is, the features of its distribution and the structure of the basins.
