Coastal Landscapes

Waves
1. Constructive wave:Waves that build up the coastline by depositing the material on it.
  1. Low energy, short waves, creates beaches, rolls onto the beach, strong swash, weak backwash, high wave frequency.
2. Destructive wave: Waves that erode the coastline.
  1. High energy, tall waves, crashes onto the beach, erodes the beach, weak swash, strong backwash, found on steep beaches, high proportion in their length.
3. Swash:: Movement of waves up a beach caused by wind.
  1. Backwash: Movement of waves down a beach (always at a right angle).
Erosion
1. Hydraulic Action- Waves forces air into cracks in the rock, air expands and the rock cracks.
2. Crrrasion- Sand and pebbles carried by the waves are thrown against the cliff and breaks it down.
3. Corrsosion- Acid reaction causes rocks to dissolve
4. Cliff Erosion
  1. Geology- Softer the rock the more erosion will take place (clay). The harder the rock the longer it will take to erode (limestone).
  2. Fetch- (Distance a wave has traveled). Longer the wave the more time the wave has had to build up-Taller the wave the more energy it has=more erosion.
Weathering
1. Physical Weathering- Water gets through the cracks of the rocks and freezes it which expands and cracks.
2. Biological weathering- Plant grows in the crack of the rock and as the plant goes bigger the rock cracks and then breaks.
3. Chemical weathering- Acid in the rain water causes a chemical reaction in the rock to dissolve.
Mass movement
1. Slumping- Large area of land moves down a slope. On clay cliffs during a dry weather the clay cracks when it rains and this causes water to get through the cracks and this makes the rock heavy and starts to slip down.
2. Soil creep- Gravity will pull water in the soil down a slope and the soil will move down the slope slowly. The slope ripples and forms terracettes.
Headlands and bays
1. Headland-Land taht sticks out into the sea. (hard rock)
  1. Bays- Area of land between two headlands. (sodt rock)
Formation of a.......
1. Stack/ stump: 1) waves erode a crack in the rock through hydraulic action. 2) Erosion will continue to widen the fault to form a cave. 3) In a headland, cave erode to form an arch. 4) Arch widens due to erosion and it will collapse because of gravity. 5) A column of rock is left behind. 6) Erosion will lead to a stamp.
2. Spit/ bar: 1) Prevailing wind brings waves into an angle. 2) Leads to long-shore drift. 3) Coastline changes direction- beach material deposited-spit formed. 4) Spit becomes curved due to change in wind direction. 5) If spit formed in a bay it may cause a bar to form with a lagoon behind it.
3. Wave cut platform: 1) Weather weakens the top of the cliff. 2)The sea attacks the base of the cliff forming a wave-cut notch. 3)The notch increases in size causing the cliff to collapse. 4)The backwash carries the rubble towards the sea forming a wave-cut platform. 5) The process repeats and the cliff continues to retreat.
Happisburgh, Norfolk
1. -Diannes Wrighton's cliff tea-shop has been destroyed. - Farmers lost land - Hotel owners lost business as tourist numbers had decreased. - Home owners forced to move, insurance increased.
  1. Effects on people: New shoreline management plans means that the population of 850 in Happisburgh will not be protected from coastal erosion. --- The area was defended in 1958 but in 1995 the council stopped as it wasn't an afective cost.
  2. Effects on the environment: Fastest eroding area in the world.-- Habitats destroyed.
  3. Economic effect: Homes use to cost ~£80, 000 and now its £1.00
Engineering techniques:
1. Hard engineering:
  1. Seal wall
    1. Absorbs energy, protects base of cliff and properties.
    2. Expensive to build and maintain.
  2. Groynes
    1. Prevents long shore drift, allows beaches to be built up, beach protects cliff/land built behind it, erosion slowed down.
    2. Easily damaged.
2. Soft engineering:
  1. Cliff engineering
    1. Reduces slumping, cheap, low cost to maintain.
    2. Proeprties on cliff needs to be demolished, needs other methods to protect erosion waves.
  2. Beach rebuilding
    1. Looks natural, good for tourism, absorbs wave energy.
      1. Constant replacement, expensive.

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Coastal Landscapes

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	Created by minalkhan_11 over 10 years ago