Knickpoint Retreat

Knickpoint retreat is the upstream migration of a sharp break in a river channel long profile, such as a waterfall, rapid or sudden change in gradient, as the concentrated erosive power at the break wears the channel bed back over time. It is the mechanism by which a stream progressively adjusts its whole profile toward equilibrium after a base-level fall, and the retreat of Niagara Falls upstream through the Niagara Gorge over roughly the last 12,000 years is the textbook illustration of the process. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/