REJUVENATION

REJUVANATION

When the base level of a river is dropped, it is considered to be revitalized.

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Isostatic change

• When land rises or falls relative to sea level as a result of crustal movement.
  
  

Eustatic Change

• The rise or fall in sea level resulting from the expansion or contraction of an ice cap.

Knickpoint

• A point in a river channel where the slope grade abruptly changes.
• The river downcutting as a result of terrain uplift causes an extremely deep river meander, or "incised meander."

Graded Profile

• A graded stream has a lengthy profile that is in balance with the landscape's overall slope.

Causes of Rejuvenation

• When the gravitational potential energy of a river increases, it rejuvenates.
• It forces the river to erode its bed vertically in order to reach balance with the landscape's slope.
•  The natural long profile of a river is a concave curve, sharper at the beginning and milder towards the finish, which is why rejuvenation is required.
• When a change in sea level disrupts the river's course, it erodes its way back to a concave curve.

Types of rejuvenation include:

 Dynamic Rejuvenation

• When land rises owing to faulting, the river must commence active downhill erosion as a result of isostatic shift
• A global sea level shift as a result of ice caps melting or forming is known as eustatic rejuvenation.
• When sea levels fall, the river's mouth experiences eustatic rejuvenation, and the river erodes its way back to its source, forming waterfalls, rapids, and incised meanders.
  
  

 Static rejuvenation

• Caused by a reduction in load or an increase in run-off, generally in the upper course of the river after glaciers melt. This results in deeper troughs.

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