distinctive landscapes

• floodplains

  wide valley floor on either side of a river that occasionally gets flooded
• levees

  1. during a flood, eroded material is deposited over the whole floodplain
  2. the heaviest material is deposited closest to the river channel because it gets dropped first when the river slows down
  3. over time, the deposited material builds up, creating levees along the edges of the channel
• meanders

  1. the current is faster on the outside of the bend because the river channel is deeper (less friction to slow the water down)
  2. so more erosion takes place on the outside of the bend forming river cliffs
  3. the current is slower on the inside of the bend because the river channel is shallower
  4. so eroded material is deposited on the inside of the bend forming slip-off slopes
• ox-bow lakes

  1. erosion causes the outside bends to get closer (of a meander)
  2. until there’s a small bit of land left between the bends (called the neck)
  3. the river breaks through this land, usually during the flood
  4. and the river flows along the shortest course
  5. deposition eventually cuts of the meander
  6. forming an ox-bow lake
• v-shaped valley

  1. in the upper course, fast flowing water and heavy rain causes loose rough particles and boulders to be transported and scraped along river bed (abrasion)
  2. the valley sides are exposed to weathering
  3. the river doesn’t have enough energy to erode sideways so vertical erosion of the river bed is dominant, which deepens the river valley, creating a steep sided v-shape
• waterfall and gorges

  1. waterfalls from the river flows over an area of hard rock followed by an area of softer rock
  2. the softer rock is eroded by hydraulic action and abrasion more than hard rock, creating a step in the river
  3. as water goes over the step it eroded more and more of the softer rock
  4. a steep drop is eventually created, this is a waterfall
  5. the hard rock is eventually undercut by erosion. it becomes unsupported and collapses
• drainage basin 


  watershed - area of high land forming the edge of a river basin

  source - where the river begins

  mouth - where the river meets the sea

  confluence - the point at which two rivers meet

  tributary - a smaller river or stream that joins a large river

  channel - where the river flows
• spits

  formed by longshore drift:

  1. waves follow the direction of the prevailing winds
  2. they usually hit the coast at an oblique angle
  3. the swash carries material up the beach in the same direction as waves
  4. the backwash then carries material down the beach at right angles, back towards the sea
  5. over time, material zigzags along the coast
• stump formation 


  crack - headlands have weaknesses

  cave - waves crash into headlands and enlarge cracks, mainly by hydraulic action and abrasion

  arch - continued erosion deepens cave until it breaks through the headland

  stack - erosion continues to wear away the rocks supporting the arch until it collapses

  stump
• headlands and bays

  1. some types of rock are more resistant to erosion than others
  2. headlands and bays form where there are alternating bands of resistant and less resistant rock along a coast
  3. the less resistant rock is eroded quickly and this forms a bay
  4. the resistant rock is eroded more slowly and is left jutting out, forming a headland
• deposition in a river occurs when

  • the volume of water in the river falls
  • the amount of eroded material in the water increases
  • the water is shallower
  • the river reaches the sea or a lake at its mouth
• coastal deposition: constructive waves

  • waves that deposit more material than they erode
  • they have a low frequency
  • swash is powerful and it carries material up the coast
  • the backwash is weaker and it doesn’t take a lot of material back down the coast
  • this means theres a lot of deposition and little erosion
• transportation

  • traction - large particles are pushed along the river bed
  • saltation - pebble-sized particles are bounced along the river bed
  • suspension - small particles like silt and clay are carried along by the water
  • solution - soluble materials dissolve in the water and are carried along
• erosion 


  hydraulic action - waves crash against cliff

  abrasion - sediment drags along sea bed

  attrition - sediment collide with each other

  solution - sediment dissolves