Formation of a gorge

Landforms in upland regions are dominantly created by erosion processes, where land is worn away.  Generally, the volume and discharge of rivers in upland regions tends to be low, and the river uses much of it's energy in overcoming friction.  The erosion direction here is vertical, or straight down into the bed of the river.  This has the effect of destabilising the slopes on either side of the river, creating a steep landscape.

As shown on the left, near to the Kunar River in Pakistan.

Waterfalls

Waterfalls are one  of the most spectacular landforms found in the upper valley and are created by erosion processes. They occur where a band of hard rock (e.g.

granite) overlies a softer rock (e.g. sandstone).

Erosion processes such as Hydraulic Action (the force of the water) and Abrasion (where the river rubs stones that are being transported against the bed of a river thereby breaking it down) dominate.

The softer rock is eroded quicker than the harder rock and gradually washes away downstream.

This creates a plunge pool where