The upper course of the river is also known as the youth stage of the river.
Rivers normally originate in mountains from glaciers or from lakes.
The path along which the river flows is known as the course of river.
The river is young in the upper flow of its course.
The upper course of a river generally lies is a hilly area.
And at this stage, the flows fast over a steep slope.
Along river’s course, it erodes its bed and banks.
River also carries large boulders and rocks at this stage.
The erosion action is large and effective under the impact of rush of water and the load of the river carries.
Therefore, in the upper course of the dominant activity of a river is erosion.
River erodes vertically at this stage.
And many land forms are shaped by this activity of the river.
Let’s discuss the landforms associated with the upper course of river.
The significant landforms resulting from erosion in the upper course of a river are- V-shaped valley and Waterfall.
V-shaped valley
A V-shaped valley is a narrow valley that has a profile suggesting the form of the English alphabet ‘V’.
It is formed due to downward erosion of river through a process called down cutting.
These valleys are formed in the initial stages of rivers and have steep slopes.
In regions of hard rock it develops almost vertically in an I-shape.
These valleys are called I-shaped valley.
River valleys are normally formed in areas of sufficient rainfall and where rocks are not very hard or resistant.
An example of V-shaped valley is the Grand Canyon in the South-western United States.
Waterfall
A waterfall is defined as a vertical fall of river water which descends suddenly from a higher level to a lower level.
A waterfall generally formed due to large differences in the rate of erosion.
The smaller difference leads to formation of step like features known as rapids.
Waterfall generally formed at the edge of the hard rock lying on a soft rock.
The soft rocks get eroded more than the hard rock.
The soft area become deeper and creates a hollow basin called plunge pool.
As a result the water rushes own almost vertically and form waterfall.
The highest waterfall in the world is Angel Falls (986 m) in Venezuela.
Niagara Falls is also famous a waterfall in the world.
Revision
The upper course of a river generally lies is a hilly area. And at this stage, the flows fast over a steep slope.
In the upper course of the dominant activity of a river is erosion. River erodes vertically at this stage and forms many landforms.
The significant landforms resulting from erosion in the upper course of a river are- i. V-shaped valley ii. Waterfall
A V-shaped valley is a narrow valley that has a profile of the English alphabet ‘V’ which formed due to downward erosion of river.
A waterfall is defined as a vertical fall of river water which descends suddenly from a higher level to a lower level. Like, Angel Falls, Niagara Falls.