Features

• V-shaped Valley:

  • Freeze thaw action weakens the cliff
  • River erodes vertically forming a gorge
  • The river cliff undermines the slopes above causing slumping and sliding
  • Slops adjust to wider v-shape due to weathering and mass movement
• Waterfall:

  • Softer rock on the river bed gets eroded quicker than hard rock
  • River erodes the softer rock vertically creating an overhang of the hard rock
  • A plunge pool is created at the bottom of the overhang due to hydraulic action and corrasion.
  • The overhang collapses while the river keeps on eroding the softer rock below it.
  • The waterfall continues to retreat up stream due to successive overhang collapses.
  • A gorge is formed where the waterfall once was
• Meander:

  • The river starts as a straight channel with alternating bars of sediment
  • The river begins to move side to side in the channel as the water flows more slowly where the bars of sediment are compared to it being faster on the other side
  • Erosion is greatest on the outside of the bends where the water is moving the quickest
  • The river continues to erode the outer bends as it extends sideways and downstream
• Oxbow Lake:

  • The neck of a meander gets thinner due to erosion
  • The river continues to deposit load onto the bars of sediment (river beaches)
  • The river breaks through the neck of the meander during a flood
  • The river deposits load blocking off where the meander once was creating an oxbow lake
  • The oxbow lake fills up with organic material as plants die
• Levees:

  • A levee is a natural river bank
  • After a flood, the river bed is built up with deposition leaving the river raised above the floodplain
  • Finer silt gets spread across the floodplain and remains there once the water has drained
  • Every time the river floods, coarser sand gets deposited near the channel building a levee