In the natural setting, the river is a watercourse that remains in permanent motion (not stagnant) and that connects with other larger waterways such as lakes, seas, oceans or other rivers, in which it precisely flows. In general, rivers serve as a connection between the different regions and those larger water courses such as the sea or the ocean.
In addition, normally, rivers are fresh water courses unlike what happens with the sea, which makes them an essential element for human, animal and plant survival. Rivers can have a completely variable length, extension, depth and width from one case to another.
Formation, characteristics, types and environmental importance
These are important portions of fresh water located inside the mass of the continents, with a diversity of flows, that is, with variations in the amount of water they transfer. Secondary streams or rivers that flow into a main river are called tributaries. Meanwhile, the surface that runs through the main river and its tributaries is called the basin.
Rivers can also fall from a cliff and thus generate waterfalls popularly known as waterfalls, which have a fantastic tourist attraction around the world, among the most famous cases the Iguazu Falls stand out. These famous waterfalls are located on the Iguazú River, located precisely on the border between the Argentine province of Misiones and the Brazilian state of Paraná. They have been duly chosen as one of the Seven Wonders of the World and of course enjoy special protection for the beautiful landscape they represent and the native flora and fauna that make it up.
The rivers are continental waters that run off through their channel on the surface of the continent and in that course they leave sediments of mud, sand, small rocks.
Rivers are perhaps one of the most changing forms of water of all known. In the first place, this is so because the water in the rivers is in permanent movement and fluctuation. Second, because this constant flow means that the same river can see its flow completely changed throughout the year, according to the amount of rainfall, drought, etc. In very few cases the rivers do not connect with another larger watercourse to get lost in the middle of the earth and dry up. However, as has been said, in most cases, rivers cross huge or small regions to finally connect with seas, oceans or lakes. Thus, they also allow navigation and the development of activities of great importance for human beings.
We cannot ignore the importance of the river with regard to the communication that they establish with other areas, navigable rivers open precisely the door of communication between neighboring populations for example.
And from an ecological point of view, rivers constitute one of the most important water reserves in the world for the living beings that inhabit the planet, in addition to being the natural environment in which countless numbers and forms of life live, among they are moneras, fungi, vegetables, plankton, animals, among others.
The extent of a river can be divided into three major parts: the upper course (where the river begins, usually between the mountains, as a thaw), the middle course (where its erosive power is softened) and the lower course (where forms meanders or sharp curves in lower areas near the sea). The lower section of a river can take various forms, for example deltas, islands or estuaries.
Some of the most important and recognized rivers in the world are the Nile (the longest in the world), the Amazon, the Río de la Plata (which ends in an estuary because it is a wide and deep mouth of water), the Danube, the Duero , the Orinoco and the Mississippi, among others.
Other uses of the concept
On the other hand, the concept of river has other uses in our language that derive from the mentioned use. When there is an abundance of something liquid, it is spoken in terms of a river: “it was a river of blood”; or when there is a tremendous influx of individuals: "on the coast there was a river of people, it was impossible to walk at times."
