River stages
A river is often divided into three parts or stages and has features that are specific to each stage.
The table below explains the main features of each stage.
| Stage | Main activity | Main features |
| Upper course (steep gradient) | Vertical (downward) erosion | Source, tributaries, V-shaped valley, interlocking spurs, waterfalls, rapids, gorges |
| Middle course (gentle gradient) | Lateral (sideways) erosion starts, transportation | River beaches (slip-off slopes), meanders, river cliffs |
| Lower course (very low gradient) | Deposition | Floodplains, oxbow lakes, levées, delta, estuary |
| Stage | Upper course (steep gradient) |
|---|---|
| Main activity | Vertical (downward) erosion |
| Main features | Source, tributaries, V-shaped valley, interlocking spurs, waterfalls, rapids, gorges |
| Stage | Middle course (gentle gradient) |
|---|---|
| Main activity | Lateral (sideways) erosion starts, transportation |
| Main features | River beaches (slip-off slopes), meanders, river cliffs |
| Stage | Lower course (very low gradient) |
|---|---|
| Main activity | Deposition |
| Main features | Floodplains, oxbow lakes, levées, delta, estuary |
River landscape
The following three diagrams show various types of river landscape.
Upper course of river
Middle course of river
Lower course of river