I have studied how the fluvial process of erosion has resulted in the creation of the waterfall   landform.

Waterfalls are sheer vertical falls in the channel of a river. Examples of well known waterfalls are the Niagra Falls in USA/Canada and Powerscourt Waterfall in Wicklow, Ireland.

Waterfalls are found in the upper course of a river.   Waterfalls form when a river flows across a band of hard rock onto a band of softer rock like in Diagram 1.

An example of hard rock is granite. The softer rock could be sandstone or limestone.

Hard rock won‛t erode very easily when the river reaches it, any softer rocks on the downstream side are eroded more quickly.   Erosion is the wearing away of the land .   The types of erosion that form waterfalls is hydraulic action and abrasion.

Hydraulic action is when the sheer power of the water erodes the land.

Abrasion is when the rivers load erodes the banks and river bed.

This means that the river bed gets steeper where it crosses the hard rock and a waterfall forms, followed by an
outcrop of overhanging rock   as can be seen in Diagram 2.

Diagram 3 shows how the overhang eventually collapses and waterfall moves upstream.

From diagram 4 you can see how   at the foot of the waterfall the water wears away the softer rock to form a plunge pool and as the waterfall retreats, it eats its way upstream and a gorge (steep sided valley) is formed.