On every continent rivers flow, large and small, they are not only fed by lakes, seas and oceans, but also provide fresh water cities and towns.Since ancient times people have tried to build their settlements near water.Today, almost every capital city, be it Moscow, Paris or Tokyo, is inextricably linked to the largest river, which was once based.But what is a river system where it originates and where it falls?
Concepts
It would not be the seas and lakes, if they did not fill every second of waterways that extend network on all continents.They take their origin or in the mountains or from a spring on a hill on the way of its flow are continuously fed by rainwater that provide watersheds.The main river is usually a large volume of water, gives the name of the system, which is constructed of the tributaries flowing into it.As an example, systems such as the Volga or the Yenisei.However, the selection is not always the main artery and tributaries so unequivocally.Usually pay attention to the selection parameters such as length, direction of flow, the structure of banks, the color and the amount of water.What is a river system can be understood by looking at the Amazon, its circuit is symmetrical and clear.
Pools
whole area of land to which the power of the river, called it a swimming pool.It generally takes the form of an ellipse or a shape reminiscent of a pear.Its value is directly exerts a strong influence on the economic and political life of the residents in the area of peoples, cities and countries.Everyone knows that water - it is life, and where it is not enough, for example, in Africa, nothing can grow.That is why our wise ancestors tried located near water.If you look at the percentage of space occupied by the pools separately on every continent, we can conclude that the most favorable in relation to the hydrographic conditions of the country are located in the South (67%) and North (49%) of America.Of course, because there are major river systems of the Amazon, the Orinoco, the Mississippi and Colorado.
Watersheds Watersheds - a conditional line or lines, which pools are separated from each other.The main watershed of the planet is called ocular (AA Tillo) and shares the swimming pool of the Arctic and Atlantic Oceans, which occupies 53% of the land and drain region of the Pacific and Indian oceans, they accounted for only 25%.This distribution is due to the structure of the earth's surface, because the coast the last two oceans dotted with various ups that complicate the path of rivers, and great importance is the amount of precipitation.The remaining 22% of the land belong to the so-called zero-discharge area, which is characterized by the fact that the river flowing there, do not have access to the seas and, therefore, to the ocean.One of the largest drainage area is Central Africa with its Sahara and Kalahari deserts.What is a river system without a watershed?The largest and most important watersheds are on the tops of the main mountain ranges.For example, in America it is the system and the Cordillera of the Andes, the Alps in Europe.
Asia
Hydrography each continent is unique and has its own peculiarities.Most of the rivers of Asia running its origins in the Himalayas and the Tibetan Plateau, these include the Indus, Brahmaputra, Ganges, Irrawaddy, Mekong, Yangtze, Salween and Yellow River.These rivers are the main arteries of life, because they are fed by all the rich nature of the area and fall as a result of freezing in the warm sea.You can highlight another feature of Asian rivers, some of them can be divided into pairs, because each pair has its origins in one place, but then they disperse to meet again at the point of runoff.It Irtysh and Ob, the Ganges and the Brahmaputra, the Tigris and Euphrates rivers, the Amu Darya and Syr Darya.Almost every river and river system are navigable because the territory in which they take place, are presented plains.
Europe
Waterways is much inferior to the Asian both in length and width.The main feature may be called proximity origins, which ultimately leads to a star-divergence rivers, a prime example - it Valdai Hills with her originate rivers such as the Volga, the influx of ilmenite, the Dnieper and the Western Dvina.The types most pools are plain, but can be combined, because they are near the mountains.
North and South America and Africa
But the share of these continents account for most full-flowing river and long.In North America, most of the waterways of the Lake belongs to the type, they feed the world's largest freshwater lakes.In the Rocky Mountains south of the continent there is a river, which gives its waters in the Pacific and in the Atlantic Ocean, it is the corresponding name "Two Oceans".In Africa, the pattern of the river system are usually interrupted by a waterfall that does not allow to develop navigation, but it applies only to the lower reaches.But in the north of the mainland flow known rivers such as the Nile, Niger and Congo.They are characterized by the absence of the watershed, which causes them to merge in the upper reaches.So we looked at what the river system, especially its distribution and structure of the basin.
