The surface of the globe is covered by more than half of the salt water of the oceans and seas. People who live on the continents and islands, use for their existence and economic activities fresh water. And they take it from rivers, lakes and other water bodies. If we give a classical definition, then the river is a stream of water that has a natural origin and flows from the top down. The beginning of the river is called the source, and the place of its confluence into another reservoir is the mouth. In this context, a well-founded question arises: what is a delta? This term also denotes the place where the river flows into another body of water.
If you look at the world map or globe, you can see that small rivers flow into lakes and large rivers. And large rivers carry their waters to the seas and oceans. Depending on the characteristics of the landscape and the geological structure of the earth's crust, the place where the river flows into the sea can take various forms. The most common in its structure is a normal mouth. In this case, all boundaries of land and water bodies are clearly visible. When this boundary is difficult to determine, it becomes clear what a delta is. First of all, it should be noted that this is an independent region with its own landscape and geological structure.
At this point, from the main channel, numerous branches branch off. Since the flow force here drops sharply, all rock debris, sludge and other solid particles precipitate. On the outside of the site, there is contact between sea and river water. As experts say, there is interaction between marine and continental environments. Fishermen on the Volga are very well aware of what a delta is. Here an original habitat of the plant and animal world was formed. It differs from the conditions that formed on the mainland, and is not like a marine abode. It is in these places that eggs of sturgeon fish spawn.
And not only fish choose such places for spawning. In such conditions, many kinds of animals and, of course, people are active in an active way of life. Everyone knows that the delta of the Nile has become a cradle for many civilizations. The foundations of modern farming were laid in ancient Egypt. This river carried a life-giving moisture to many peoples who inhabited the adjacent territory. Already in those days people knew perfectly well what delta is and what it means to the farmer. The most fertile soils accumulated here. Another thing is that the cultivation of crops is always associated with various risks - the water level will rise before the time, the crocodiles will breed.
It should be noted that at the confluence of the sea delta formed by two mechanisms. In the first case, the river carries in its waters a large volume of sedimentary rocks and gradually, as they say, comes to the sea. The edge of the shore moves deep into the water area. But it also happens that the strong current of the river flushes a deep canal in the mouth. And then, instead of an alluvial soil base, an estuary is formed at this place. Liman is a reservoir in which river and sea water is mixed. An example of such an education is the delta of the Dnieper. In such places it is very good to spend hot summer days, but nature does not provide any opportunities for agriculture.