Rivers - Long Profile
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.
Rivers - Upper Course
The diagram below shows the typical characteristics of the upper course of a river valley.
Typical features of the upper course of a river:
Rivers - Middle Course
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:
Rivers - Lower Course
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:
Rivers - Changes in Profile
In the source area the drainage basin (an area of land drained by a river and its tributaries) contains V shaped valleys and waterfalls, and the dominant processes are erosion. Erosion tends to be vertical (straight down into the land).
In the middle section of the drainage basin the river starts to erode laterally (side-ways). This section contains meanders and Ox bow lakes, and the river creates a flood plain often with Levees. Here, Material is deposited and erosion can also occur.
In the lower drainage basin deposition dominates as a river enters a sea or lake, the valley is at its widest and deltas and estuaries are major landforms and habitats.
Rivers - The Bradshaw Model
The Bradshaw Model attempts to show what should happen to various river characteristics from source to mouth along its long profile.
There are many changes that occur in rivers as a result of changes within the water cycle and drainage basin. The diagram below summarises the changes that occur: