DEPOSITIONAL LANDFORMS

• levee characteristics

  • raised river banks
  • made of stones, gravell and alluvium
  • grading of sediment
  • steep sided
  • flat top
• levee formation

  1. during flooding the friction of land reduces water velocity leading to depostion
  2. heaviest sediment is dropped first closest to the river bank
  3. as distance from the river increases sediment size gets smaller
  4. after many flooding events the levees rise in height
• floodplain characteristics

  • large area of flat land either side of a river prone to flooding
• floodplain formation

  1. width if floodplain determined by meander migration as lateral erosion forms valley edges
  2. as a river floods and receeds the floodplain gets higher and becomes fertile as silt and alluvium are deposited
  3. sediment on the floodplain builds up over 100s of years raising the floodplain overtime
• estuary characteristics

  • high tidal range
  • very wide
  • visable mudflats at low tide
  • tidal bores cause damage to the river bank and vegetation
• estuary formation

  1. post glacial rise in sea levels creates an estuary due to flooding
  2. river flows towards the sea increasing in salinity
  3. mixing of fluvial and marine sediment
  4. flows slow down and deposition occurs
• mudflats

  form in sheltered areas as the river deposites sediment - fresh and salt water mix causing the velocity to drop