The rivers Are flows or streams of fresh water that are born in the mountains and hills, and travel to the lowest parts of the earth, being the terrestrial relief the determining factor of its main characteristics.
It is there, in the highlands, where its birth occurs, also called its source of origin or head.
They emerge by means of mouths or exits, in lakes or seas, through channels called drains that were generated during many years.
In turn, these channels, which can be of different sizes and depths, flow down the water, in search of its mouth.
The rivers contain fresh water and in it, a aquatic world full of life. They increase or decrease their flow depending on various factors, such as climatic changes, geological, or those produced by man himself.
Through the different geographical spaces present in the earth, the river takes its course, always in constant movement, to find its mouth.
How does the birth of a river occur?
The place where a river is formed or born corresponds to its source or its head. It is from there from where the water flows, which travel by long trails, until its mouth.
However, the birth of a river can occur in various ways. One of them refers to the water that flows from the earth, which was deposited underneath it. Product usually of the fluvial precipitations.
This accumulation of this underground fluid is previously produced by rain. That is to say, in the rain it is filtered or deposited under the earth, an amount of water that when grouping or accumulating, emerges naturally towards the surface.
Before this happens, this liquid from below the Earth has traveled previously for several kilometers in which are present diverse sediments and rocks that act like natural filters, removing of the water any type of contaminant existing in her, and Besides, providing it of diverse minerals.
That is why rivers are considered natural sources of water of excellent quality and rich in minerals, where the mineral water is usually extracted for processing.
Another form referring to the birth of the rivers, alludes to the rainfall in the high parts of the earth, such as mountains or hills. This water is not absorbed by the earth, running down the surface of it, towards lower parts.
Also the rivers can have their origin from the melting of the glaciers, following the flow or stream of the water the course from a higher part or cusp to a lower one.
These waters, which in their course come together by growing the river bed, are those that later form streams or streams.
What is the course of a river?
The course of a river makes reference to the route that this one realizes, from its birth, until its opening in another river, or in the sea.
The course of a river is also called a river course, presenting several characteristics, including varying lengths, slopes more or less inclined, greater or lesser amounts of water, among others.
In the mountain where the river finds its origin, are different formations known as basins, by means of which, the river begins to form when the water passes by means of them.
The basins present at the top of the hills and mountains, are characterized by being narrow and steep. They are usually surrounded by valleys and geological formations that produce changes in direction to which the river adapts as it finds its way through them.
The more slope exists, that is, the closer to the head of the river, we can visualize that the water will flow faster, which is how the waterfalls are generated.
At the same time, in its rapid flow, the water is generating the wear of the natural materials that it finds in its passage, producing its erosion.
From each basin, the river begins to glide forming what is called a stream.
When these different basins are combined, the streams originate, which join together forming larger flows and flows of water, finally merging into a river and giving rise to the river basin.
These channels and streams are what are called the tributaries of the rivers. Now, rivers may flow into a lake, or into the sea, but they can also flow into another river, these being the tributary rivers.
What are the characteristics of the course of a river?
The course or course of a river is characterized by three sections. From the head down you can find a high course, an average course and a low course.
High Course
The high course of a river includes its head, that is to say where it originates and the first kilometers of its route. It is the place where great slopes predominate, which cause that the river flows with high energy and with great speed.
In the upper course of the river, its channel is narrow and shallow. This is where the emerged waters flow to the surface that gave rise to the formation of the river.
The speed and the force with which the river moves in this section, produced by the great slopes present in the head, cause that the water forms channels or deep gorges giving origin to the waterfalls.
Middle School
The average course of a river, refers to the area where it flows more smoothly, because the slopes have a lower degree of inclination with respect to the high course.
At the same time, in its middle course, the river increases its course by merging with its tributaries, eroding the earth and depositing its sediments, along its path to its mouth.
In the middle course of the river is where small curves or ripples can be produced, which are called meanders, due to the decrease in the speed in which the water flows and the change of course that it undergoes.
Low Course
In the lower course of a river, the level of the slopes is already almost nil, so the slope is small.
For this reason the speed of water is much lower than in previous courses, even at first sight it seems static.
It is in its lower course, where the river deposits the largest amount of materials it carries, giving rise to alluvial plains.
At the same time, in the lower course of the river is where the lakes, or the sedimentary islands called deltas produced by the sedimentation of the materials that the river drags, can form.
It is in the lower course of the river where the different mouths of the river are produced. These being his final stretch. This is where they usually form large estuaries, composed of a wide mouth and deep river and where the fresh water is mixed with the salt water of the sea.
References
1. Baird, D.M. (1965). Glacier and Mount Revelstoke National Parks: Where the Rivers are Born.
2. Jolley, R. (2008). Effects of Sedimentation on Productivity, Nutrient Cycling and Community Composition in Riparian Forests Associated with Ephemeral Streams at Ft. Benning, GA, USA. ProQuest.
3. Judy L. Meyer, Ph.D., University of Georgia; Louis A. Kaplan, Ph.D., Stroud Water Research Center; Denis Newbold, Ph.D., Stroud Water Research Center; David L. Strayer, Ph.D., Institute of Ecosystem Studies; Christopher J. Woltemade, Ph.D. (2007). Where Rivers Are Born: The Scientific Imperative for Defending Small Streams and Wetlands. Retrieved from Williametteinitiative. Excerpted from willametteinitiative.org/tools-resources/where-rivers-are-born.
4. Kathleen C. Weathers, D.L. (2012). Fundamentals of Ecosystem Science. Academic Press.
5. Likens, G. E. (2010). River Ecosystem Ecology: A Global Perspective. Academic Press.
6. WHERE RIVERS ARE BORN: THE SCIENTIFIC IMPERATIVE FOR DEFENDING SMALL STREAMS AND WETLANDS. (N.d.). Retrieved from Americanrivers. Excerpted from americanrivers.org.
7. Where Rivers are Born: The Scientific Imperative for Defending Small Streams and Wetlands. (2003). Sierra Club.