River Rejuvenation( knick points )

River rejuvenation is is the rivers base level is lowered.This can be caused by a rise in the ground level or a drop in the sea level.
A drop in base level gives the river greater potential energy increasing vertical erosion.

Knick points- horse shoe falls Canada

A knick point will form and mark the junction between the original long profile and the new long profile.

An example is the Horseshoe falls Canada

My As books example