Role of rivers in nature
The river is a significant amount of water flow flowing along the channel (deepening in the earth’s surface) from the source (the beginning of the river) to the mouth (the point of entering another reservoir). The river collects its waters due to surface and underground drains. Basically, as a result of precipitation. Therefore, in the dry seasons, the channel can dry up, and in rainy, on the contrary, overflow. The floodplain part of the river valley is called floodplain.
The river came out of the shores
The author of the photo is fvanrenterghem, the link to the original (photo has been changed).
The main rivers are those that directly flow into any reservoir, with the exception of other rivers (lakes, seas, oceans), or simply end. All other rivers fall into the main, and are called tributaries. The main river, together with all its tributaries, is called the river system.
The area with which the river system collects water is called a catchment basin (also called the catchment area, catchment area, or river basin). The conditional line dividing the two catchment basins is called the watershed.
Rivers, as a rule, do not have constant depth. In them, alternating parts of relatively large depth (plyosy), and small (rolls) alternate. If throughout the length and width of the river to measure the depth, and to find the deepest sections of the river, then you can make the line of the greatest depths, it is called talvegom. As a rule, river vessels go exactly on this line, since it is impossible to allow the ship to land in a hurricane. This safe route for ships is called a fairway. Especially good, when the line of the greatest depths coincides with the line of the fastest current (стрежемем), but this does not always happen.
The fall of the river is called the difference between the heights of its source and the mouth. And the ratio of indicators of the fall of the river to its length is called a slope. For example, 5 cm on 1km.
In the event that the height difference in a particular area is sharp and significant, it is called a waterfall.
The most popular way to classify water bodies is by far the largest. Large rivers are those that have a basin area of more than 50,000 km2 in the event that they flow in the plain, as well as mountain rivers with an area of more than 30 thousand km2. The middle rivers are called those that have a catchment area of 2 to 50 thousand km2. Well, small ones have a swimming pool area not exceeding 2 thousand km2.
Another method of classification – in depth. True, the rivers can not compete in this indicator with other reservoirs. The deepest rivers in the world have a number close to two hundred meters in this graph. What is not enough.
Among other things, the most clean and most interesting rivers of the world are singled out.
The rivers are used by man from ancient times. They have always served as one of the sources of fresh water, and sometimes the only one. They were also used and used to this day for the production of food (fish). In our time, of course, this is not so critical, but before it was very important. This is one of the reasons why some reservoirs were called sacred and erected in a cult.
The rivers are used for shipping. Even today, this is very important, as it is possible to transport large volumes of cargoes to long distances along river shipping routes, which is quite economical. Well, in the middle ages, navigation was at all the fastest and safest way to travel long distances. It was near the rivers that arose many large cities, and, importantly, flourished at the expense of trade.
It is difficult to overestimate the importance of rivers for human beings. They are used for irrigation of agricultural fields and for extraction of energy (hydropower plants and water mills). Many people simply swim in the rivers, and half a century ago they were still used for economic needs (washing clothes, for example), because there was no water pipeline. And with their help get rid of waste (not necessarily harmful). The rivers serve as natural boundaries between states, and during battles they were still used as defensive lines.
The significance of the rivers is so great that it is difficult to imagine even how we lived without them. Fortunately, this is not required, because they have! And it’s really cool.