Each river has a source - the place where it originates, and a mouth - the area of its confluence with another watercourse. Water streams that connect with oceans, seas or lakes are the main ones, and those that flow directly into the river are called tributaries.
They flow in valleys, that is, places whose relief is elongated and lowered. The point of maximum decrease is the river bed. The floodplain is the part of the valley that is constantly flooded with river water.
River - what is it?
A river is a stream of water, often formed naturally. It flows in a certain direction from its source to its mouth; feeds in various ways: snow, glacial, underground and other waters.
Watercourses are formed due to the accumulation of water in the valley. As a rule, the reason for their formation is abundant and regular precipitation, melting of snow, ice, etc. When building dams ordams form reservoirs, which can be lakes or even seas. However, in this case, they will have no flow, and they are most often created artificially.
Basically, all watercourses flow along faults in the terrain, there is no resistance and tension.
Current
As mentioned above, the river bed is a place in the valley, the level of depression of which reaches its maximum mark. It is divided into several types. One of them is the mainstream. This is the name of a certain area on the river, in which there is a large part of the watercourse.
Depending on the size of the riverbed can reach a huge width, which varies from one meter to several tens of kilometers. At the same time, the depth does not increase simultaneously with the expansion of the watercourse. And very often it happens that in the place of a large spill there is shallow water. In mountain rivers, channels can have rapids, as well as waterfalls. According to their trajectory, they distinguish the winding lower part of the valley - in the flat rivers, and the straight line - in the mountain ones.
The former river bed is called the oxbow lake. As a rule, it is presented in the form of a sickle, a loop or a straight line. It is formed when, due to a strong current, a water stream breaks a new path. After that, most of the water does not fall into the old channel and the so-called oxbow lake is formed. Eventually it either dries up or becomes completely overgrown with aquatic plants.
Changing the course of a river is often artificial. In that case, this leadsto irreversible consequences, which are then difficult to eliminate.
Floodplain
Floodplain is a part of the river that is constantly flooded during floods or floods. Often its dimensions depend on the width of the channel, but not always. It can vary by several meters, and sometimes even kilometers.
Floodplain soils are fertile only if the waters of the stream that flood a piece of land bring silt. As a rule, this place is great for fishing.
Terraces are areas of former floodplains, the water level in which is several times higher than in the channel, even during floods and floods.
Source and mouth of the river
The source of a river is the place where it begins. Often these are small swamps or streams. If the river system has a lot of sources, the one that is either the most abundant or the most distant from the mouth of the watercourse will be considered the main one. Very often, the beginning of a river can be considered the confluence of reservoirs or streams.
A mouth is a place where a watercourse flows into. It can be any lake, sea, reservoir, another river. It is different in its structure. For example, sometimes a delta or a lip may form at the confluence of a river with a body of water.
The riverbed, floodplain, source and mouth are not all that characterize rivers. In addition to them, there are also banks (watercourse boundaries), reaches (places with the greatest depth), rifts (areas with the least depth). And those sections of the river in which the strongestthe speed of the current, were called the rod.
