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.

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.