CASE STUDY - Jurassic Coast

• Location

  The Dorset Coast is located on the south coast of England

  
• its called the Jurassic coast because it has fossils dating from the jurassic period
• 3 Landforms formed by geomorphic processes:

  • durdle door : arch
  • Old Harry + Wife : stack + stump
  • Swanage Bay : bay
• durdle door

  Formed by hard limestone headland
• old harry and his wife

  made from chalk (hard rock)

  • vegetation on top is breaking up the rock by biological weathering
  • carbonation weathering is eroding them currently
• Swanage bay

  the cliffs backing the bay is made of clay, a soft rock
• the hard rock there: chalk and limestone

  soft rock: clay and sandstone
• temperature

  • warm dry summers around 21˚C
  • mild wet winters around 3˚C
  • no freeze thaw weathering as it’s not cold enough
• wind

  • prevailing winds from the SW
  • can bring storms from Atlantic oceans, bringing high energy destructive waves which increase cliff erosion
  • Hydraulic action and abrasion Increase during storms
• rainfall

  low amounts annually, but can experience very wet winters

  • soils and rocks are heavier when saturated, making them prone to mass movement
• 3 coastal management techniques used here:

  • groynes
  • sea walls
  • beach nourishment
• Groynes

  • wooden fences built at a right angle to the coast
  • They trap transported material from Longshore drift
  • They create wider beaches which slow down waves
  • Protect against erosion, and large beaches are good for tourism
  • However starve beaches further down the coast of sediment, making them narrower
  • 19 new ones installed in 2005/06
• sea walls

  • concrete sea walls against cliffs in Swanage beach
  • reflect waves back out to sea, preventing erosion
  • however can create a strong backwash, removing sediment, lowering the level of the beach
• beach nourishment

  • adding sand to a beach to build it up
  • larger beaches appeal to tourists
  • costs £5 million as sand needs to be imported from elsewhere
  • done every 20 years
• tourism

  • Around 5 million tourists at the Jurassic coast every year
  • Coastal footpaths along cliff tops are worn down as people walk on them
  • The vegetation is trampled and worn away
  • This exposes underlying soil and rock to weathering and erosion by wind and rain