Human life has always been closely linked to the rivers.It was not only in the past, there is such a link today.Its people are always the first settlements were built on the waterfront, close to the sources of fresh water.They were used for fishing and irrigation as a means of communication, it was floated on the forest.Today, all major cities in the world are located on large rivers, and their names sound like synonyms in London and the Thames, the Seine and Paris, St. Petersburg and the Neva River, New York and the Hudson.
Even at school we all know what the river, as well as the fact that the water flow moves in the recess called mainstream.Each of them, like everything else in this world has a beginning, it is called a source.A confluence of the sea, ocean or lake is called the mouth.
Water flow can also indulge in other, larger size.The main track with all its tributaries form the river system.
Every river, regardless of size, has its own swimming pool - a certain area, which it collects surface water and groundwater.The boundary separating the pools is called a watershed.
mode and power
Talking about what a river should definitely mention about her mode.Meals surface water and groundwater, as well as consumption takes place during the year is uneven.As a result of seasonal changes in the water level line and other factors.
mode is usually divided into several periods.What is a river in flood, we saw everything - the annual recurring spill at one and the same time can not be overlooked.The water level in the channel increases so much that it overflows its banks.Equally clearly expressed and a different period - low water.At this time, the water level is the lowest, which is caused by a decrease in revenues from its catchment area.And then there are floods - flash-level rise caused by heavy rainfall or rapid snow melt too.
What they are
depending on the form of relief for which they take place, water flows are divided into two groups:
- plains;
- mountain.
rivers flow slowly on a flat surface, as their sources are at low altitude, and slope of the terrain on which they take place, small.Valley they are wide, with gentle slopes.One example is China's great rivers: the Yangtze and Yellow.These are known to us as the Volga, Dnieper, Don and others.
in the mountains for a very rapid, since the sources are located high and the mouth - on the plains.The slope of the territory significantly, in line with the water moving at high speed, "slotting" in hard rocks for hundreds of thousands of years of narrow valleys with steep slopes.What is a river flowing in the mountains?It is strength and power, unstoppable torrent, rushing for tumbleweed and rapids.Perhaps the most prominent representative of this group is the Yenisei.
part of the flow, which starts in the mountains, leaving the plane, change their character from turning into mountain plains.Examples include some of the rivers of Bashkortostan, the origins of which are located on the western slopes of the Ural Mountains.The main waterway of the republic - p.White, on the picturesque banks of which are located towns and villages.Coming down from the mountain spurs, flowing through the plain Priuralsky and collecting water on their way numerous tributaries, it becomes power and shipping.
