Changes from source to mouth
The long profile of a river is a way of displaying the channel slope of a river along its entire course. Therefore, it shows how a river loses height with increasing distance towards the sea.
The diagram below shows the typical characteristics of the upper stages of a river valley.
Typical features of the upper course of a river:
The middle course of the river has a wider floor and the sides of the valley are more gently sloping. The velocity is slower than the upper stage. However, the channel is wider as the amount of water flowing in it increases as other streams and rivers join it.
Typical features of the middle course of a river:
The lower course of the river is very gentle sloping, almost flat. The channel is usually at its widest and deepest here because the amount of water flowing within the river is at its greatest.
Typical features of the lower course of a river: