UPPER COURSE FEATURES

UPPER COURSE FEATURES

1. EROSION

   • The process by which the rock or soil is gradually destroyed by the wind , rain or the sea. Erosion can be vertical or lateral.
   • Solution
     • Acidic water eroding away alkali ricks such as Limestones.
   • Hydraulic Action
     • The force of the water breaking open cracks in the rocks.
   • Abrasion
     • Rocks and pebbles hitting the banks and bed of the river eroding it away.
   • Attrition
     • Rocks hitting each other and chipping down into smaller pebbles.

2. TRANSPORTATION

   • Traction
     • Large boulders roll along the river bed.
   • Saltation
     • Pebbles and stones bounce along the river bed.
   • Suspension
     • Small pebbles are suspended in the river water.
   • Solution
     • Tiny particles are dissolved in the water and move along.

3. Formation of 'V' shaped valleys

   • 'V' Shaped Valley
     • Rivers move over land surface eroding material by abrasion and hydraulic action.
   • Vertical Erosion
     • Gravity means that erosion leaves a 'V' shaped valley.
   • Weathering
     • Weathering causes the sides of the valley to weaken.
   • Mass Movement
     • Mass movement removes weakened material.

4. FORMATION OF WATERFALLS

   • 1) The soft rock erodes more quickly, undercutting the hard rock.
   • 2) The hard rock is left over hanging and because it isn't supported, it eventually collapses.
   • 3) The fallen rocks crash into the plunge pool. They swirl around causing erosion.
   • 4) A steep sided gorge is formed as the waterfall retreats.
   • 5) Over time this process is repeated and the waterfall moves upstream.

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