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|
The following three diagrams show various types of river landscape.