coastal landscape in the uk

• what is mass movement?

  a large movement of soil and rock debris that moves down slopes
• what are the steps of mass movement?

  -rain saturates the permeable rock above the impermeable rock making it heavy

  -waves will erode the base of the slope making it unstable

  -eventually the weight of the permeable rock above weakens and collapses

  -the debris at the bottom is removed by waves
• what are constructive waves?

  the swash is stronger than the backwash so it builds up the coast
• what are destructive waves?

  the backwash is stronger than the swash which therefore erodes the coast
• what is carbonation weathering?

  the breakdown of rock by changing its chemical composition
• what is mechanical weathering?

  the breakdown of rock without changing its chemical composition
• what are the stages of freeze thraw weathering (mechanical)?

  -water seeps into cracks and fractures in the rock

  -the water freezes it expands and wedges the rock apart

  -with this repeating the rock will break off
• what is deposition?

  when the sea loses energy and drops sediment it has been carrying
• what are the types of erosion?

  attrition - rocks bash together to become smooth

  solution - a chemical reaction that dissolves rocks

  abrasion - rocks hurled at the base of a cliff to break pieces apart

  hydraulic action - water enters cracks in the cliff, air compresses causing the crack to expand
• how does longshore drift work?

  -swash moves up the beach at the angle of the prevailing wind

  -backwash moves down the beach at 90 to the coastline

  -zigzag movement transports material along the beach
• how do bays and headlands form?

  -waves attack the coastline

  -the softer rock is eroded by the sea quicker forming a bay

  -the more resistant rock is left jutting out into the sea which forms a headland
• what are the processes of transportation?

  traction - large particles are pushed along the sea flour

  suspension - small particles are carried along the water

  saltation - pebble sized particles are bounced along the sea bed

  solution - soluble material dissolve in the water and are carried
• how does is a stack formed?

  -hydraulic action widens the cracks in the cliff face over time

  -repeated erosion causes the cracks to form a cave

  -continued erosion eventually breaks through the headland to form a arch

  -erosion continues to wear away the rock supporting the arch until it eventually collapses to form a stack
• how is the wave cut platform formed?


  -through hydraulic action and abrasion the cliff face becomes eroded causing a notch to form

  -the notch is eroded larger and creates a overhand above

  -this gets repeated causing the cliff to retreat creating a platform
• how are spits formed?

  -swash moves up the beach at the angle of the prevailing wind

  -backwash moves down the beach at 90 to the coastline

  -zigzag movement transports material along the beach

  -deposition causes the beach to extend

  -change In the prevailing wind forms a hook
• what waves form sandy beaches?

  low energy constructive waves
• what waves form pebble beaches?

  high energy destructive waves
• what are the steps for the development of sand dunes?

  -embryo dunes form around deposited obstacles

  -this dune builds up and the growth vegetation such as marram grass stabilises the dune forming a foredune and a yellow dune

  -winds can form depressions between lines of dunes called dune slacks
• what are the hard engineering defences?

  groynes - prevents longshore drift

  sea walls - break up the energy of the wave and redirects the waves back

  rock armour - cages of rocks to absorb the waves energy
• what are the disadvantages or hard engineering?

  groynes - no deposition further down the coast so it is left exposed

  sea walls - expensive to maintain and build

  rock amour - will need replacing
• what are the soft engineering strategies?

  beach nourishment - sediment is put back on the beach to create a buffer between land and sea

  beach reprofiling - sediment is pushed back up the beach to create a buffer

  managed retreat - low value areas are left to flood
• what are the disadvantages of soft engineering strategies?

  beach nourishment - needs replacing, can damage the seabed with dredging

  beach reprofiling - shuts the beach of and can be expensive

  managed retreat - compensation for land