A mouth is a part of a river that flows into a sea, lake, reservoir, another river or other body of water. This area is characterized by the formation of its diverse and rich ecosystem. Some reservoirs have a non-permanent mouth. This is due to the fact that large streams dry up in some places. Sometimes it happens that the point of confluence of water bodies is subjected to excessive evaporation.
In the Old Russian language, the meaning of the word "mouth" had several meanings. So they could designate not only the final section of the river, but also its source or headwaters.
Blind Estuary
Mouths are different, for example, blind, it disappears. This can happen as a result of evaporation, seepage of the channel into the ground, or the intervention of a person who irrigates the fields. The shape of the mouth depends on many factors: the presence of tides, the characteristics of the soil and the climatic zone, the strength of the current. The mouth is in some cases a fickle place, especially when the river changes its course, directionor runs into a swamp.
Delta
If a river, when it flows into another body of water, is divided into many branches, channels and islands, then the mouth may be called differently. Such a special area is usually called a delta. It owes its name to its similarity in shape to a triangle. For the first time, the Nile mouth was so named. This suggests that such a formation is often formed when the river flows into closed water bodies, without pronounced tides. At the same time, the strength of the current near the coastal strip decreases, the applied material settles and compacts, forming islands, then spits, from which sleeves are subsequently formed. This place connected the Nile with the Mediterranean Sea.
Deltas can be different in number of sleeves, but more or less elongated in their shape. 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 is near the Ganges, it is 105.6 thousand square meters. km, the next largest near the Amazon River - 100 thousand square meters. km. It should be noted that the delta can form not only within the mouth of the watercourse, but also upstream.
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." S alt water in such cases can rise high in the channel, which prevents the formation of deposits from sedimentary rocks. In addition, it formsthe depth that 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 Garonne and Dordogne rivers. In Russia, the largest formations of this kind formed on the rivers Ob and Yenisei, which flow into the Kara Sea.
The mouth and the source, although sometimes, are located tens of kilometers apart and really have a strong influence on themselves. The general characteristic of the intermediate flow depends on the basin of one or another section. Fish populations, current speed, vegetation, environment, wildlife on the coast - all this depends on the mouth and source.
