River landforms

Landforms in the upper course

V-shaped valley

Man stood in a v-shaped valley

When a river is near its source, it often develops a V-shaped valley as the river erodes down (this is called vertical erosion). At the same time, weathering breaks up material on the valley slopes. Weathered material from the valley sides gets deposited in the river. This material is carried by the river and erodes the riverbed through abrasion.

Waterfalls

Waterfalls often form in the upper stages of a river where it flows over different bands of rock. It erodes soft rock more quickly than hard rock and this may lead to the creation of a waterfall.

Formation of a waterfall:

  • The soft rock erodes more quickly, undercutting the hard rock.
  • The hard rock is left overhanging and because it isn’t supported, it eventually collapses.
  • The fallen rocks crash into the plunge pool. They swirl around, causing more erosion.
  • Over time, this process is repeated and the waterfall moves upstream.
  • A steep-sided gorge is formed as the waterfall retreats.
Waterfall formation diagram