What is a river, what are the rivers

Human life has always been closely connected with rivers. It was not only in the past, there is such a connection today. People always built their first settlements on the banks of water bodies, closer to fresh water sources . They were used for fishing and irrigation, as a means of communication, they were melted in the forest. Today, all major cities of the world are located on large rivers, and their names sound like synonyms: London and Thames, Paris and the Seine, St. Petersburg and the Neva, New York and Hudson.

Since the school day, we all know what a river is, as well as the fact that this water stream moves in a depression called a bed. Each of them, like everything in this world, has a beginning, it is called the source. And the place of confluence in the sea, ocean or lake is called the mouth.

The water flow can also flow into another, larger in size. The main channel with all tributaries form a river system.

Each river, regardless of size, has its own basin - a certain area with which it collects surface and groundwater. The boundary dividing the basins is called the watershed.

Mode and power

Talking about what a river is, it is necessary to mention her regime. The supply of surface and groundwater, as well as consumption, occurs unevenly throughout the year. As a result, the water level in the riverbed and other indicators vary by season.

There are usually several periods in the mode. What is the river in flood, everyone saw - this yearly repetitive spill at the same time can not be overlooked. The water level in the riverbed rises so much that it comes out of the banks. Another period is equally pronounced - intermittent. At this time, the water level is the lowest, which is caused by a decrease in its intake from the catchment area. And there are still floods - a sudden rise in the level caused by heavy precipitation or too rapid melting of the snow.

What are they like?

Depending on the shape of the relief along which they flow, water flows are divided into two groups:

• Flat;
• Mountain.

The flow of rivers on a flat surface is slow, since their sources are at a negligible height, and the slope of the terrain over which they flow is small. The valleys are wide, with sloping slopes. An example is the great rivers of China: the Yangtze and the Yellow River. The same applies to the known to us Volga, Dnieper, Don and others.

In the mountains the current is very rapid, since the sources are high, and the estuaries are on the plains. The slope of the territory is considerable, the water in the riverbed moves with great speed, narrowing through hard rocks for hundreds of thousands of years, narrow valleys with steep slopes. What is a river flowing in the mountains? It is strength and power, an uncontrollable stormy stream, rushing along the rapids and rapids. Perhaps, the brightest representative of this group is the Yenisei.

Often flows that begin in the mountains, coming out on a plane, change their character, from mountainous to flat ones. Some rivers of Bashkiria, whose origins are on the western slopes of the Ural Mountains, can serve as an example . The main water artery of this republic is r. White, on the picturesque shores of which are cities and towns. Descending from the mountain spurs, flowing along the Ural Plain and collecting on its way the waters of numerous tributaries, it becomes sedate and navigable.