Describe and Explain the formation of a waterfall.

Firstly a waterfall is defined as a cascade of water falling from a height over a steep incline or precipice. It is typically found in the upper course of a river and in formed via vertical erosion. They are four key types of erosion.1) Attrition 2)Corrosion3)Abrasion 4)Hydraulic action Waterfalls form when a river flows over bands of soft (less resistant) and hard (more resistant) rock. Due to the soft rock being less resistant it is erode away first. Therefore overtime, the soft rock is erodes away and the hard rock begins to be undercut, via abrasion and hydraulic action. This leads to the formation of an unsupported overhang which eventually collapses into the plunge pool. The rocks are swirled around in the plunge pool, and via abrasion it is enlarged. Overtime this process is repeated and the waterfall retreats upstream. Eventually this will lead to the formation of a steep-sided gorge.