What is a river bed? What parts (segments) is it divided into? What relief forms are formed within the river bed?
Each of us knows what the river and its channel look like. It can be narrow or wide, shallow or deep, permanent or temporary. What is a channel from the point of view of science? You will find the answer to this question in our article.
What is a channel: definition and essence of the concept
A river is a water stream of natural origin, characterized by a relatively large size. And any river in the world has a channel. What is it?
Hydrologists can talk about what a river bed is. These are scientists who study a variety of water bodies. Not only rivers, but also lakes, swamps, reservoirs, etc. But only the rivers have what we are going to consider in detail in this article. So what is a channel?
A channel is a gutter on the surface of the earth through which a water stream flows. This is the lowest element of the river valley. At the same time, one important point should be noted: the channel, being the basis and “foundation” for the river, is formed by it.
The channels can vary greatly in appearance and size. In large rivers (such as the Volga, Dnieper or Amazon), their width can reach several kilometers. At the same time, the channels of small watercourses and rivulets a person is able to easily jump. In lowland rivers, the channel is usually winding and multi-arm, and in mountainous rivers it is more direct and heavily cluttered with stones, boulders, and tree trunks.
So, we figured out what the channel is. Now find out how it changes the relief of the surrounding area.
Channel processes and their features
To better understand the question of what a channel is, you should familiarize yourself with the processes that occur in it.
Channel processes mean the totality of processes and phenomena that ultimately lead to a change in the shape and parameters of river channels. For the first time, they began to study them back in the Middle Ages. So, the famous Italian scientist Galileo Galilei worked on a project to straighten the bends of the Tiber in order to reduce the level of floods that annually flooded Rome. Today, channel processes are studied by a special scientific discipline - channel science.
The basis of these processes is the interaction of flowing water and the underlying surface. The river destroys rocks, transports them to certain distances and lays (accumulates) in a new place. As a result of these processes, the river valley itself changes and takes on new forms.
Hydrologists usually divide the riverbed into three parts (sections):
- upper course (destructive processes dominate here);
- middle course;
- lower course (the processes of accumulation of geological material destroyed in the upper reaches of the river prevail here).
Man has learned to significantly modify river channels. Active anthropogenic interference allows you to change their shape (for example, straighten water flows), depth and even direction. All this, of course, cannot but affect the dynamics of natural channel processes.
Channel formations: fords, streams, rifts and waterfalls
As a result of the mechanical work of the river channel, a number of specific formations and relief forms are formed:
- ford;
- zastruga;
- plyos;
- roll;
- threshold;
- waterfall and others.
A ford is a shallow section of a riverbed through which a river can be crossed on foot or by vehicle. In the Middle Ages, large fords often spanned entire cities. Today, many names of settlements are associated with this term: for example, the city of Brody in Ukraine, Havlíčkv Brod in the Czech Republic, Oxford in the UK (ford translated from English - “ford”).
Elders are elongated sandy or sandy-pebble spits located under water. Ples is a deep section of the river channel that forms along the concave shore of the meander.
The bed of mountain rivers and rivulets is very often complicated by rapids, streams and waterfalls. Thresholds are formed in those places where very strong rocks come to the surface that the river is not able to erode and destroy. A waterfall is a unique geomorphological formation, a rocky ledge in the riverbed from which water freely falls down.
River bed bifurcation
River bifurcation is an interesting and rather rare natural phenomenon. The term itself comes from the Latin word bifurcus, which means "forked". Bifurcation is the division of the channel (including the river valley) into two independent water streams. In the future, these streams no longer connect and flow into different bodies of water. Most often, this phenomenon is observed on flat rivers that flow along a flat, level earth surface.
The most famous example of channel bifurcation in the world is the Orinoco River in South America. In the upper reaches, the Kasikyare branch branches off from it. Subsequently, it adjoins the Amazon river system, taking with it about a third of the entire Orinoco runoff.
Finally…
What is a river bed? The definition of this concept and its detailed study is one of the tasks of the science of hydrology. The channel is one of the main elements of the river valley, a natural gutter along which the water stream directly moves.
In the riverbed, processes of destruction, displacement and accumulation of geological material are constantly taking place. As a result of these processes, specific microforms of the relief are formed: fords, zastrugi, streaks, rifts, rapids and waterfalls.