Processes forming river landscapes - upper course

Formation of a v-shaped valley and waterfall

V-shaped valley

Formation of a V shaped Valley

Formation of a V-shaped valley

  • Rivers begin high up in the mountains so they flow quickly downhill eroding the landscape vertically.
  • The river cuts a deep notch down into the landscape using hydraulic action, corrasion and corrosion.
  • As the river erodes downwards the sides of the valley are exposed to freeze-thaw weathering which loosens the rocks (some of which will fall into the river) and steepens the valley sides.
  • The rocks which have fallen into the river help the process of corrasion and this leads to further erosion.
  • The river transports the rocks downstream and the channel becomes wider and deeper creating a V-shaped valley between interlocking spurs.

Erosion

Waterfall

Formation of a WaterfallFormation of a waterfall

  • The river flows over bands of softer and harder rocks.
  • Softer rock is more quickly eroded.
  • The river undercuts the harder rock leaving an overhang.
  • The river forms a plunge pool below the waterfall.
  • Overhanging rock is unsupported and falls into the plunge pool.
  • The waterfall is moved upstream.
  • This process continues and a gorge is cut back into the hillside.

Waterfalls, plunge pools and potholes