Coastal Erosion

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Coastal Erosion
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Forces That Shape The Earth

• The Earth is shaped by both internal and external
  processes
• Internally, tectonic processes form the
  lithosphere
• Externally gradational processes also shape the
  lithosphere
• These include rivers, winds, glaciers, and waves

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Rivers

• Rivers cut deep valleys and create large deltas

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Winds

• Winds carves beautiful rock formations and carry
  sands

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Glaciers

• Glaciers flow over continents while slowly
  carving out the land and dropping large boulders

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Waves

• Waves and currents cut into coastlines and polish
  sandy beaches.

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The Other Gradational Force

• Humans are a gradational force
• This picture is an example of the effects of over
  forestation

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Coastal Erosion

• The constant battering of the waves (14,000 waves
  per day)
• Effects
• erode the shoreline
• transport the eroded material
• deposit the eroded material elsewhere

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Factors Affecting Coastal Erosion

• Softer rocks are more easily eroded
• Sea floors that slope gradually have less erosion
  because wave break offshore
• Coastlines oriented perpendicular to prevailing
  winds erode more easily
• Rising sea levels increase erosion rates.

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Signs of Coastal Erosion

• Wave-cut notches An indentation cut into a sea
  cliff at water level by wave
• Sea caves cave formed primarily by the wave
  action of the sea
• Sea arches form where cliffs are subject to
  erosion from the sea
• Sea stacks steep and often vertical column of
  rock in the sea near a coast, isolated by erosion

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Wave Cut Notch
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Sea Arches, Caves, Stacks
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Sea Arches and Sea Stacks
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Elephant Rock, PEI
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Hopewell Rocks, NB
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Preventing Coastal Erosion

• Riprap a heap of angular boulders piled along
  the shoreline
• Breakwater a wall of boulders built parallel to
  the shore to take the brunt of the breaking waves

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Rip Rap
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Breakwater