As a waterfall retreats, it leaves behind the steep-sided valley which is called a gorge. Every time the overhanging rock breaks off the gorge retreats and grows longer.

Find out more about the landforms of erosion in the upper course of a river.

The characteristics of rapids include:

• the turbulent flow of water
• white water
• uneven river bed
• steep gradients.

Find out more about the landforms of erosion in the upper course of a river.

Interlocking spurs are fingers of land that jut out into the river valley that streams and rivers are forced to flow around in the upper course.

Find out more about the landforms of erosion in the upper course of a river.

Rapids are fast flowing, turbulent sections of the river where the bed has a relatively steep gradient. They are found in the upper course of the river.

Find out more about the landforms of erosion in the upper course of a river.

A waterfall is a step in the long profile of the valley. It is where water falls down the vertical drop in the channel usually from a considerable height.

Find out more about the landforms of erosion in the upper course of a river.