The upper course of a river is found in an area of high relief. The long profile starts at the source of the river. Water trickles from saturated land and merges to form a channel.
Source of a river
The channel then flows downwards following a steep gradient. The steep channel gives the river more potential energy. In the upper course, there may be rapids and waterfalls as the river flows through steep V-shaped valleys.
The upper course of a river with rapids as the river flows through steep V-shaped valleys.
Erosion in the upper course of the river is mainly vertical by hydraulic action.
Transportation mainly involves large boulders being moved by traction.
Large boulders are deposited in the upper course of the river.