uk costal landscapes

• wave fetch - how far it’s travelled
• factors that effect the size of a wave

  • fetch
  • wind strength
  • how long the wind has been blowing for
• destructive wave

  • weak swash
  • strong backwash
  • close together + steep
  • remove sediment
• constructive wave

  • weak backwash
  • strong swash
  • low wave and far apart
  • deposits sediment
• freeze thaw weathering

  1. water enters a crack in the rock
  2. water freezes and expands the rock
  3. water melts
  4. process repeats until the rock breaks
• biological weathering

  1. roots begin to grow in a crack
  2. roots grow and the crack gets wider
  3. rock breaks away
• hydraulic action

  • power of wave as it smashes against a cliff causes air to become trapped in cracks
  • this causes rock to break apart
• abrasion

  • rocks grind along a rock platform
  • smooths rock over time
• attrition

  • rocks in the ocean hit against eachother
  • break apart becoming smaller and smaller over time
• solution

  • sea water dissolves certain types of rocks such as chalk or limestone
• formation of a wave cut notch/platform

  1. erosion causes cliff to retreat
  2. weather weakens cliff
  3. notch increases and cliff collapses
  4. wave cut notch
  5. wave cut platform

  
• saltation

  • small pieces of rock and sand are bounced along the sea bed
• traction

  • large pieces of rock are rolled along the sea bed
• longshore drift

  • waves approach the coast at the angle of prevailing wind
  • the swash carries sediment to the beach at an angle
  • the backwash then carries sediment back to the ocean
  • this process repeats in a zigzag moving sediment down the coast
• deposition occurs when the sea looses energy and drops the material it was carrying
• when a coastline is formed from different rocks the rate of erosion happens at different rates

  this leads to the formation of headlands and bays
• Formation of bays

  • bands of soft rock eg clay and sand erode quicker than the surrounding hard rock
• A bay is an inlet of the sea where the land curves inwards, usually with a beach
• A headland is a narrow strip of land projecting into the sea, usually at the end of a bay

  A headland is more likely to have features like a wave cut notch and platform as it’s more exposed to waves
• Bays are sheltered from wind with constructive waves which deposit sediment to form a beach
• wave cut platform

  • waves attack the base of a cliff and erode it inwards to form a dent (notch)
  • as the notch increases in size the cliff above becomes unstable and collapses
  • the backswash carries away eroded material leaving a wave cut platform
  • this process repeats as the cliff retreats
• The formation of a spit occurs when longshore drift deposits sand along the coastline forming a curved bar of shingle or pebbles that extends into the sea
• spits grow over time due to deposition of sediments by long shore drift
• formation of a stump

  1. crack in the rock
  2. this erodes into a cave
  3. caves becomes larger and eventually opens through the headland to form a arch
  4. base of the arch becomes wider due to erosion until its roof becomes too heavy and collapses
  5. this leaves behind a stack
  6. the stack is undercut at its base until it collapses to form a stump
• sand beaches are usually in bays where its sheltered

  this causes the waves to become constructive ( loosing energy) and deposit sand

  This builds to form the sandy beach
• Pebble beaches are usually at the base of cliffs where rock has eroded
• formation of spits

  1. sediment is carried by longshore drift
  2. there is a change in the shape of the coastline deposition occurs
  3. a long thin strip of sediment is deposited ( the spit )
  4. waves can’t get past a spit so behind the water is very shelterd
  5. this can cause the formation of salt marshes and mud flats
• Sometimes spits can grow across a bay and join two headlands. This is known as a bar. They can trap shallow lakes behind known as a lagoon
• lagoon

  • water behind a bar
• main process that form caves

  • hydraulic action
  • abrasion
• sea walls

  • curved concrete at the foot of a cliff that reflects the energy of a wave
• advantages of sea wall

  • effective at protecting the base of a cliff
  • sea walls usually have promenades for people to walk along
• disadvantages of a sea wall

  • waves can still erode the sea wall
  • expensive
• Rock armour

  • large boulders at the bace of a cliff to break the waves and absorb its energy
• advantages of rock armour

  • cheaper than a sea wall
  • easy to maintain
  • can be used for fishing