estuary

Each stream flows from the source, where it takes itsbeginning, and, gaining strength, ends at the mouth of the river, where it flows into another pond (ocean, sea, lake, other river or reservoir). It follows that the mouth of the river - this is the place of its connection with another reservoir. Some do not have a permanent mouth, sometimes they lose it in a swamp, so tracing the end of the stream is not always possible.

There is the concept of the so-called blind mouth. It can appear as a result of drying or when water seeps into the ground, sand, or the river flows into a lake without a lake.

It is customary to distinguish such types of estuaries as delta and estuary:

• The delta of the river is due to the appearance of deposits of erosion products and their removal in large quantities;

• estuary - flooded lower part of the valley.

In the event that at the mouth of the river the sea is shallow, nottidal currents are expressed, and the river takes a rather large amount of sediment, then we can safely say that nature has created all the conditions for the appearance of the delta.

An example of the world's largest delta is thethe mouth of the Amazon. Its area is more than one hundred thousand km². Just in this delta stretched another record holder - Marazho, a huge river island, exceeding the area of ​​Scotland. The Amazon River staggers its mouth, it exceeded the width of the English Channel ten times. Therefore, it is not surprising that in the rainy season, the river begins to leave its shores and thus floods the adjacent forests. It is very rich in fish and vegetation. There are some species of animals that live only in the Amazon. Because of the width it is not so easy to cross it, it will take about four hours for this.

Estuaries are formed where in the mouth of the riverthere is a descent of the coast. The Ob river is the largest estuary. It is called the Ob Bay, its length is about 800 km, 50-70 km wide and 25 m deep.

The rivers that flow into the cold Arctic seas,differ in the types of their mouths. For example, the Lena River and others, which are to the east, have deltas. They are pronounced and go far into the sea. Those that are to the west form estuaries.

The mouth of the Dniester River, which carries its waters to the Black Seasea, characterized by such an education as the estuary. And its neighbor, the Danube, formed at the confluence of the delta. What factors contributed to this, still remain a mystery for scientists, the light on which it was able to shed only partially.

A very simple view of the delta is the beak-shapeddelta. It consists of two braids, which are on both sides of the channel. This type can be seen only on small rivers, for example, in Italy - p. Tiber. Similar braids appeared when the flow velocity in the river became small, but the current persisted on the rod.

Also not too common type is consideredlobed delta. An example of this can be seen on the Mississippi River. Its delta arose because of the furcation of the channel, in this case it is a few sleeves. Prerequisites can be different: ranging from uneven terrain, ending with the influence of the human factor.

These types of deltas are formed when they enter the seas.There is another species that is characterized by confluence into shallow bays. Such deltas still have a name - implementation. An example is the Danube River. Very interesting is the delta of the Niger, because its edge has received an even contour. A lot of effort was put to this by the surf of the sea.