On every continent, rivers flow, large and small, they not only feed lakes, seas and oceans, but also provide fresh water to cities and towns. Since ancient times, people tried to build their settlements near water bodies. And today, almost any
the capital, whether 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 come from and where does it flow?
Basic concepts
There would be no seas and lakes if every second they were not filled with water arteries, which spread the network across all continents. They take their origin either high in the mountains or from a spring on a hill, along the course of their course they are continuously fed by rainwater, which provide watersheds. The main river, usually large in volume of water, gives the name to the system, which is built from tributaries flowing into it. Examples include systems such as the Yenisei or the Volga. True, the allocation of the main artery and tributaries is not always so simple. Usually, for isolation, pay attention to such parameters as length, direction of flow, coastal structure, color and volume of water. What is a 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 feeds is called its basin. As a rule, it looks like an ellipse or resembles a pear in shape. Its magnitude directly has a strong influence on the economic and political life of 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 settle near the water.
If we look at the percentage of the space occupied by the basins separately on each continent, we can conclude that the most favorable countries with respect to 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 conventional lines or stripes along which pools separate from each other. The most important watershed of the planet is called the ocular (A. Tillo) and divides the basin of the Arctic and Atlantic oceans, which occupies 53% of all land, and the waste region 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 river paths, and the amount of precipitation is also very important. The remaining 22% of the land belongs to the so-called inland region, which is characterized by the fact that the rivers flowing there have no access to the seas and, therefore, to the oceans. One of the largest landlocked areas is central Africa with its deserts Sahara and Kalahari. What is a river system without a watershed? The largest and most important watersheds pass through
the tops of the main mountain ranges. So, for example, in America these are the Cordillera and Andes systems, for Europe these are the Alps.
Asia
The hydrography of each continent is unique and has its own characteristics. Most Asian rivers run in the Himalayas and Tibetan Highlands, including the Indus, Brahmaputra, Ganges, Irrawaddy, Mekong, Yangjiang, Saluin and Yellow River. The listed rivers are the main arteries of life, because they nourish the rich nature of these areas and eventually flow into the warm, ice-free 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 Ob, the Ganges and the Brahmaputra, the Tiger and the Euphrates, the Syr Darya and 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
The water arteries here are significantly inferior to the Asian ones in both length and width. The main characteristic feature is the close location of the sources, which ultimately leads to a star-shaped divergence of rivers, a vivid example is the Valdai Upland, from it rivers, such as the Volga, tributaries
Ilmen, Dnieper and
Western Dvina. By their type, most of the basins are flat, but can be combined, as they are located near the mountains.
North and South America and Africa
But the share of these continents accounts for the most full-flowing and longest rivers. In North America, the majority of the water arteries are of the lake type; they feed the world's largest freshwater lakes. In the Rocky Mountains of the southern mainland there is a river that gives its waters both to the Pacific and the Atlantic Ocean, it bears the name of “two oceans” corresponding to it. As for Africa, the scheme of the river system here is usually interrupted by a waterfall, which does not allow the development of shipping, 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 pools.