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River landscapes – WJEC Erosional landforms

Large scale landforms are found in the upper course of a river, meanders and floodplains are found in the middle and lower course, and small scale landforms can be found along all stages of a river.

Part of GeographyLandscapes and physical processes

Erosional landforms

The processes of can create different landforms. The erosional features are often found in the of the river.

Waterfalls and gorges (Large scale landforms)

A waterfall forms when water falls down hard rock in a steep sided gorge. A plunge pool forms. The overhang erodes and waterfall retreats.

A is a sudden drop along the river course. It forms when there are horizontal bands of resistant rock (hard rock) positioned over exposed, less resistant rock (soft rock).

  1. The soft rock is eroded quicker than the hard rock and this creates a step.
  2. As erosion continues, the hard rock is undercut forming an overhang.
  3. and continue to erode the soft rock to create a (small scale landform).
  4. Over time this gets bigger, increasing the size of the overhang until the hard rock is no longer supported and it collapses.
  5. This process continues and the waterfall retreats upstream.
  6. A steep-sided valley is left where the waterfall once was. This is called a .

V-shaped valleys

A spur is land jutting out causing a river to meander. Interlocking spurs cause rivers to keep meandering through a V-shaped valley.

In the upper course there is more vertical erosion as the river is less powerful, so material cannot be moved in and is instead moved along the river bed using traction or saltation. This erosion, together with the movement of weathered material at the sides of the river, creates the classic V-shaped valley. If there are areas of hard rock which are harder to erode, the river will bend around them.