Section C

• Freeze- thaw weathering

  1. water enters the cracks in the rock
  2. the water freezes and expands, putting pressure on the rock.
  3. the ice thaws, releasing pressure
  4. repeated freezing and thawing causes the rock to break apart.
• what are the 3 types of mass movement?

  sliding, slumping and rock fall
• sliding mass movement 


  material slides quickly downwards in a relatively straight line
• slumping mass movement 


  material slides with a rotation over a curved slip plane.
• rock fall mass movement


  rocks break apart and fall, often as a result of freeze-thaw weathering
• what are the 4 types of erosion?

  • abrasion
  • attrition
  • hydraulic power / action
  • solution
• hydraulic action


  This is the sheer power of the water as it smashes against the river banks. Air becomes trapped in the cracks of the river bank and bed, and causes the rock to break apart.
• Abrasion -

  • When pebbles grind along the river bank and bed in a sand-papering effect.
• Attrition -


  When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.
• Solution


  When the water dissolves certain types of rocks, eg limestone.
• what are the 4 types of transportation?

  traction, saltation, suspension, and solution
• Traction


  large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the load is larger.
• saltation 


  smaller items of sediment bounce along the seabed
• suspension


  finer material is light enough to be carried by the water
• solution

  • Solution - the transport of dissolved chemicals. This varies along the river depending on the presence of soluble rocks.
• longshore drift

  1. Waves approach the coast at an angle.
  2. Swash carries sediment up the beach at an angle.
  3. Backwash carries sediment down the beach with gravity – at right angles to the beach.
  4. This creates a zig-zag movement of sediment along the beach.
• deposition

  • deposition occurs when the sea loses energy and drops eroded material. it is most likely to happen when:
  • low energy waves with a weak backswash
  • LSD is interrupted by structures e.g. groynes
  • little wind
• wave cut platform

  1. The sea attacks the base of the cliff between the high and low water mark.
  2. A wave-cut notch is formed by erosional processes such as abrasion and hydraulic action - this is a dent in the cliff usually at the level of high tide.
  3. As the notch increases in size, the cliff becomes unstable and collapses, leading to the retreat of the cliff face.
  4. The backwash carries away the eroded material, leaving a wave-cut platform.
  5. The process repeats. The cliff continues to retreat.
• Caves, Arches and Stacks

  1. Waves crash repeatedly into the headlands, causing faults and joints to erode and develop into cracks and small caves.
  2. constant erosion causes the cave to get bigger until their back walls are eroded away completely, creating natural arches
  3. the arches widen as more rock is eroded away through weathering
  4. the arches eventually collapse, leaving an isolated pillar known as a stack. further erosion of the stack will leave a shorter stump.
• sea walls adv / dis

  Advantages

  • Effective at protecting the base of the cliff.
  • Sea walls usually have promenades so people can walk along them.

  Disadvantages

  • Waves are still powerful and can break down and erode the sea wall.
  • Expensive - approximately £2,000 per metre
• rock armour 


  Large boulders placed at the foot of a cliff. They break the waves and absorb their energy.
• rock armour adv / dis

  Advantages

  • Cheaper than a sea wall and easy to maintain.
  • Can be used for fishing.

  Disadvantages

  • They look different to the local geology, as the rock has been imported from other areas.
  • The rocks are expensive to transport.
• sea walls 


  Concrete walls that are placed at the foot of a cliff to prevent erosion. They are curved to reflect the energy back into the sea.
• gabions adv / dis

  Advantages

  • Cheap - approximately £100 per metre.
  • Absorbs wave energy.
  • easy to construct

  Disadvantages

  • Not very strong.
  • Looks unnatural.
• groynes adv/ dis

  Advantages

  • Builds a beach - which encourages tourism.
  • They trap sediment being carried by longshore drift.

  Disadvantages

  • By trapping sediment it starves beaches further down the coastline, increasing rates of erosion elsewhere.
  • They look unattractive.
• beach nourishment adv / dis

  Advantages

  • Blends in with the existing beach.
  • Larger beaches appeal to tourists.

  Disadvantages

  • Needs to be constantly replaced.
  • The sand has to be brought in from elsewhere.
• beach nourishment 


  Sand is pumped onto an existing beach to build it up.
• beach reprofiling

  The sediment is redistributed from the lower part of the beach to the upper part of the beach.
• beach reprofiling adv / dis

  Advantages

  • Cheap and simple.
  • Reduces the energy of the waves.

  Disadvantages

  • Only works when wave energy is low.
  • Needs to be repeated continuously.
• what is in the upper course of a river?

  waterfalls, gorges, interlocking spurs,
• middle course of a river features

  meanders, floodplains,
• lower course features


  meanders, oxbow lakes, floodplains, leeves
• are waterfalls and gorges a fluvial process or coastal?

  fluvial
• waterfalls and gorges

  1. soft rock is eroded easily through hydraulic action and abrasion, enabling the river to cut down into the channel
  2. over thousands of years, the river continues to erode the soft rock, and a plunge pool develops
  3. the overlying hard rock ( cap rock ) is undercut and left unsupported until it eventually collapses
  4. the falling hard rock causes further erosion through abrasion, and the waterfall begins to retreat upstream.
• meanders

  • deposition takes place on the inside bend, where the river flows slowly. the shallow channel creates greater friction, which slows the river down.
  • erosion and transportation take place on the outside bend, where the river flows fast. the deeper channel creates less friction, which enables the water to flow quickly.
• oxbow lakes

  1. erosion on the outside bend of a meander causes the neck of the meander to become narrower
  2. the neck of the meander continues to narrow until the river eventually breaks through to form a new river channel.
  3. the river now flows along the shortest course, bypassing the loop.
  4. as sediment is deposited on the riverbanks, the meander becomes sealed off.
  5. oxbow lake forms
• leeves

  1. when a river floods over its banks, the water spreads out and slows down. as it does so, it loses energy and deposits the material it has been carrying.
  2. heavier material is deposited first, closest to the channel. finer, lighter material is carried further over the floodplain.
  3. repeated flooding and deposition forms raised leeves along the edges of the channel
• factors affecting flood risk

  • precipitation
  • geology -> impermeable rock
  • relief
  • land use
• hard engineering flood management - dams and reservoirs advantages

  Advantages

  • Can be used to produce electricity by passing the water through a turbine within the dam.
  • Reservoirs provide a water supply for nearby towns and cities.
  • Reservoirs can attract tourists.
• hard engineering - flood management dams and reservoirs disadvantages

  Disadvantages

  • Very expensive.
  • Spoil the look of the natural environment.
  • Dams trap sediment which means the reservoir can hold less water.
  • Habitats are flooded often leading to rotting vegetation. This releases methane which is a greenhouse gas.
  • Settlements are lost leading to the displacement of people. In developing countries locals are not always consulted and can have little say in where they are relocated.