To what extent can fluvial landforms be classified as belonging to the upper, middle or lower course of a river?
A logical, clear way to classify fluvial landforms is according to the one location where they can be found, but some of these belong to more than one river section. As the river advances, its characteristics and surroundings change and therefore, fluvial landforms are common at only specific river sections. However, some landforms can be found in both the middle and lower courses of a river, product of similar river features found in the different stages of its profile and therefore can be classified in more than one category.
The upper course holds unique characteristics which affect the type of fluvial landforms that take place exclusively in this portion of the river profile, showing the cross section of a river from its source to its mouth. The source or beginning of a river is usually a melting glacier or a lake in a mountainous area. It is because of this that the slope or gradient of a river at this stage is rather steep, making water flow downwards at an angle and erosion to be mostly vertical. Different types of weathering, like frost wedging, break apart the mountain rocks and tumble into the river bedload, so this will be composed of large angular boulders. This part of the river has a low discharge, which is the amount of water flowing in the cross section area of a river at a given point. This is due to the fact that most rivers in the upper course are small streams which will eventually become tributaries to a mature river as water makes its journey to reach the sea. These factors combined with the narrowness of the young river give it a turbulent and low velocity flow. This will eventually form fluvial landforms that will exclusively take place under these conditions. Such is the case of V-shaped valleys, interlocking spurs, rapids and gorges.
A logical, clear way to classify fluvial landforms is according to the one location where they can be found, but some of these belong to more than one river section. As the river advances, its characteristics and surroundings change and therefore, fluvial landforms are common at only specific river sections. However, some landforms can be found in both the middle and lower courses of a river, product of similar river features found in the different stages of its profile and therefore can be classified in more than one category.
The upper course holds unique characteristics which affect the type of fluvial landforms that take place exclusively in this portion of the river profile, showing the cross section of a river from its source to its mouth. The source or beginning of a river is usually a melting glacier or a lake in a mountainous area. It is because of this that the slope or gradient of a river at this stage is rather steep, making water flow downwards at an angle and erosion to be mostly vertical. Different types of weathering, like frost wedging, break apart the mountain rocks and tumble into the river bedload, so this will be composed of large angular boulders. This part of the river has a low discharge, which is the amount of water flowing in the cross section area of a river at a given point. This is due to the fact that most rivers in the upper course are small streams which will eventually become tributaries to a mature river as water makes its journey to reach the sea. These factors combined with the narrowness of the young river give it a turbulent and low velocity flow. This will eventually form fluvial landforms that will exclusively take place under these conditions. Such is the case of V-shaped valleys, interlocking spurs, rapids and gorges.
