The Features And Processes Of A River Along Its Profile

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The Features and Processes of a River Along Its Profile

Introduction ------------

Along the path of a river, from source to mouth, the river shows many different features and is affected by several different processes. These processes are going to be described and explained in the course of this essay and diagrams will be used to back-up and justify my ideas.

A river can be simply divided into an upland or lowland river environment. Upland features and processes occur at a higher altitude, closer to the source of the river; lowland features and processes occur at lower altitudes near the mouth of a river. A river's course can be better divided into a young, mature and old stage. …show more content…

Erosion, for example, wears rocks away through 4 sub-processes:

* Corrasion or abrasion

* Attrition

* Corrosion or erosion by solution

* Hydraulic action

Transportation can be further divided into:

* Traction

* Saltation

* Suspension

* Solution

A description of these processes and diagrams showing how they affect the river are shown below:

Erosive Processes

Corrasion or abrasion

This is when smaller material which is suspended, rubs against the river banks. This is more common in lowland areas, where the river is at a low altitude and has a low gradient.

Attrition

This is when boulders are being transported along the river bed collide and smash up into smaller pieces. This is likely to occur where river velocity is high in upland areas.

Corrosion or erosion by solution

This is when acids in the water dissolve soft rocks such as limestone.

Hydraulic action

This is when the sheer force of the river breaks up and dislodges particles from the rivers banks and bed.

Transportation Processes

Traction

Saltation

Suspension …show more content…

When there is high discharge, the high amounts of energy in the river can transport large amounts of material in suspension. In high discharge, the river often floods, spreading out across any nearby flat land. This land causes sudden increase in friction, and so velocity decreases causing much deposition of fine silt. Every time a river floods, another thin layer of silt is deposited, and a flat floodplain is formed. The heaviest material will be deposited first when a river floods, forming an embankment next to the river, called a levees. This levees acts as a natural flood defence, and are sometimes strengthened. If these levees are broken, then huge floods occur over great areas of land.

A diagram showing Floodplains and Levees

(iii) Deltas

Description

A delta is a small area of land formed from deposition when a strong current meets a weaker current.

Explanation

As a river gets closer to its mouth and the sea, the current is dramatically reduced, and its material deposited. This deposited material can block the rivers path. The river must then divide into

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