Stages of a river

The long profile of a river is a cross-sectional representation that traces the river’s course from its source to its mouth. It illustrates how the river’s gradient and characteristics change along its length, typically showing a steep gradient in the upper course, a gentler slope in the middle course, and a very flat gradient in the lower course.

The cross profile of a river changes significantly from its upper to its lower course, reflecting variations in erosion, transportation, and deposition processes. The cross profile is typically narrow and steep in the upper course, forming V-shaped valleys due to dominant vertical erosion. As the river progresses to the middle course, the profile becomes wider and shallower, with more lateral erosion creating wider valleys and the development of meanders. In the lower course, the cross profile is broad and flat as the river reaches its mouth, with extensive deposition leading to the formation of floodplains and deltas.

The diagram below shows a range of features associated with a river’s upper, middle, and lower courses.