What is estuary and how does it differ from delta

When considering large freshwater bodies, it is necessary to find out what the estuary is. The term refers to the final stretch of the river, the shape of which resembles a funnel. The mouth of such a reservoir consists of one arm and becomes wider towards the sea.

How does the estuary appear?

River and forest

Estuary, translated from the Latin language is called"Flooded mouth of the river". It has a funnel-shaped and one-sleeve shape, and can expand towards the sea. In geography, there is the opposite concept - it is the delta, which is a river mouth, divided into channels. Delta has Amazon and Nil. But the mouth of the Volga can be called a delta and estuary.

The phenomenon is observed where the ground with sand is washed out due to sea currents or tides. A depression is formed, which is closer to the salt water body. It is known that estuaries were formed by the Yenisei and the Don.

Classification

Evening over a mountain river

Scientists distinguish these formations depending on the circulation of water and the geological structure of the soil.It is believed that the most ancient estuaries were created by nature many thousands of years ago, when the end of the last ice age was approaching. This is due to lower sea levels. Such species are called coastal plains.

If parts of the rivers with depressions are isolated by the beaches from the sea, they are called barrier estuaries. These are long and narrow formations parallel to the coastline, about 5 meters deep.

Tectonic estuaries have arisen in places of subsidence of rocks under the influence of volcanoes or landslides. Fresh and sea water is collected in the hollows created by nature if the land is below sea level.

The estuaries that are created by glaciers are called fjords. Large ice blocks moved to the ocean and cut deep strips along the coastlines. After the retreating frozen water, the depressions were filled again.

Wedge-shaped estuaries are parts of rivers in which water circulates much more intensively than in others. Moreover, here the tides are considered insignificant. The freshwater layer gradually decreases in those places where the estuary is approaching the sea. The wedge-shaped layer of this site can be seen in places of denser seawater.This type is divided into several subspecies, depending on how the water mixes. So, geographers distinguish a discontinuous type, which is characterized by complete transitions.

Large estuaries of Russia and the world

Twilight over the river

The largest estuary is considered the part of the river called the Gironde. Its length is 72 km. In North Carolina (United States of America) there is a bay called Albemarl. It belongs to the large estuaries, separated from the Atlantic Ocean by a chain of Outer shallows.

If we consider the territory of Russia, we will call the estuary in the form of an estuary. These include education on the Yenisei and Ob. The Amur part of the river desalinates the local estuary. A similar mouth has the Volga, although some scientists tend to believe that its mouth is still a delta.

Video plot

The mouth is the place where the river meets another pond. Here you can see the delta or estuary. When part of the water formation dries up as a result of evaporation or human intervention, they speak of a blind mouth. And not every river has a permanent mouth. Some reservoirs of the plan in question may change course depending on the season.

In general, you need to know that delta and estuary are two opposite concepts.

Interesting information

Night, mountains, river

The longest rivers of the world

The longest river in the world is the Nile, its length reaches 6653 km. In second place is the Amazon, which flows in Brazil.

The widest rivers of the world

The list of wide world rivers includes the Kama, flowing through the territory of Russia, being the largest tributary of the Volga. We can not fail to note Amazon (the width of the delta is more than 325 km) and the Nile, which are much wider in comparison with other freshwater systems in the world.

The longest river in Russia

Russia has an extensive network of rivers, rivers and streams. Many of them do not even have a name. But there are real giants. The longest river in Russia is the Lena with a length of 4,400 km. In second place is the Irtysh, which reaches a length of 4248 km.

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