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.


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 rivers with indentations are isolated by 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 arose in the places of sedimentation 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 toward the ocean and cut deep lines along the coastlines. After the retreat of the frozen water, the depressions were filled again.

Wedge-shaped estuaries are sections of rivers in which water circulates much more intensively than in others. Moreover, here the tides are considered insignificant. The freshwater layer is gradually decreasing 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

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. The Volga has a similar mouth, although some scientists are inclined to believe that its mouth is still a delta.

The mouth is the place where the river meets another pond. Here you can see the delta or estuary. When a 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 the delta and estuary are two opposing concepts.

Interesting information

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 into Brazil.

The widest rivers of the world

The list of the world's wide rivers includes the Kama, which flows through the territory of Russia, being the largest tributary of the Volga. It should be noted Amazon (the width of the delta more than 325 km) and the Nile, which are much wider in comparison with other freshwater systems of the world.

The longest river in Russia

Russia has an extensive network of rivers, streams and streams. Many of them do not even have a name. But there are real giants. The longest river in Russia is the Lena, which is 4400 km long. In second place is the Irtysh, which reaches a length of 4248 km.

Watch the video: What is the difference between delta estuary lagoon bay gulf Straits peninsula (January 2020).

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