What does the term "undercutting" refer to in the context of river banks?

The term "undercutting" specifically describes the process of erosion that occurs at the lower part of a river bank. As the water flows along the banks of a river, it exerts force against the sediment or soil, particularly at the base. Over time, this relentless action of water can remove material from the lower sections of the bank, causing it to become steeper and potentially leading to collapses or slumping.

In this context, undercutting is crucial in shaping river landscapes, contributing to the changing course of rivers and the formation of features such as cliffs or overhanging banks. Other concepts, such as the formation of river meanders or sediment deposits, refer to different processes that do not specifically involve the erosion mechanism described by undercutting. Similarly, the spreading of flood plains addresses the area where water spreads during floods, which is a separate process from the erosive action illustrated by undercutting.