A V-shaped valley is a steep-sided valley in the shape of a ‘V’. It is shaped by vertical erosion.
Formation: • The force of moving water in the river cuts downwards into the river bed, making it deeper. This process is called hydraulic action. It creates a deep, narrow valley.
• Mechanical weathering and mass movement also weather the sides of the valley, breaking down rock and soil.
• The material that falls into the river is carried downstream as part of the river’s load.
: Figure 9.6 Formation of a V-shaped valley Examples of V-shaped valleys: the upper course of the rivers Liffey, Lee and Moy.
Interlocking spurs Interlocking spurs are areas of high ground that jut out at both sides of the V-shaped valley. Formation:
• The river flows very fast in the upper course. It makes its way downhill, winding and bending around areas of hard rock that it cannot erode.
• The river erodes vertically as it winds and bends.
• This process creates areas of high ground on either side of the river which fit together like a zip.
• Over time, as the river continues to erode, they become more pronounced, and we call them interlocking spurs. Examples of interlocking spurs: upper course of the rivers Barrow and Slaney.
