The mouth is what? Definition, description, features

The mouth is a part of a river that flows into the sea, a lake, a reservoir, another river or another body of water. This site is characterized by the formation of its diverse and rich ecosystem. Some ponds have a variable mouth. This is due to the fact that large flows in some places dry up. Sometimes it happens that the point of confluence of water bodies undergoes excessive evaporation.

In the Old Russian language the meaning of the word "mouth" had several meanings. So could designate not only the final section of the river, but its source or upper reaches.

Blind mouth

The mouths are different, for example, blind, it disappears. This can happen as a result of evaporation, seepage into the soil or interference of a person who irrigates fields. The shape of the mouth depends on many factors: the presence of tides and the features of the soil and climatic zone, the strength of the current. The mouth is in some cases a non-permanent place, especially when the river changes its course, direction or falls into a swamp.

Delta

If the river at the confluence into another body of water is divided into a number of branches, ducts and islands, then the mouth can be called differently. Such a special area is usually called a delta. It owes its name to a similarity in form with a triangle. For the first time this was called the Nile mouth. This suggests that such education is often formed when the river flows into closed reservoirs, without pronounced tides. At the same time, the flow strength near the coastal strip decreases, the deposited material settles and becomes denser, forming islands, then braids, from which sleeves are subsequently formed. This place connected the Nile with the Mediterranean Sea.

The deltas can be different in number of sleeves, and in their shape more or less elongated. All this depends on the difference in the density of the waters encountered, the strength of the current, and other factors. The largest area of the delta near the Ganges, it is 105.6 thousand square meters. Km, the next largest on the Amazon River - 100 thousand square meters. Km. It should be noted that the delta can be formed not only within the mouth of the watercourse, but also higher in its current.

Estuary

The mouth is also the so-called estuary. When rivers flow into an open body of water with strong tides, it can form in the form of a funnel (lip or firth). This word comes from the Latin "aestuarium", which means "flooded mouth of the river". Salt water in such cases can rise high along the channel, which prevents the formation of sediments from sedimentary rocks. In addition, a depth is formed, which allows the river to remain navigable. The largest estuary is the Gironde in France, which is 75 km long and was formed from the confluence of the rivers Garonne and Dordogne. In Russia, the largest formations of this kind were formed on the rivers Ob and Yenisei, flowing into the Kara Sea.

The mouth and source, although sometimes, but are tens of kilometers apart and really exert a strong influence on themselves. The general characteristics of the intermediate flow depend on the pool of a particular section. Populations of fish, current speed, vegetation, environment, animal life on the shore - all this depends on the mouth and source.