Dorset Coast-Distinctive Landscapes

• located on the south coast of England. Called the Jurassic Coast as it has a large amount of fossils- good for geologists!

  background information
• Swanage Bay (bay)

  Durdle Door (arch)

  Hurst Spit (spit and tombolo) and The Fleet Lagoon (lagoon)

  Old Harry (stack) and his Wife (stump)

  Durdle Door (beach)

  landforms x5
• The Dorset Coast has warm, dry summers (around 21°C in July) and mild, wet winters (average minimum temperature in January is 3°C.)

  Salt weathering is the dominant form of mechanical weathering, particularly in summer. Warm temperatures cause sea water to evaporate from the rocks quickly, which leaves a build up of salt crystals in tiny cracks in the rock.

  The mild winters mean that freeze-thaw weathering isn't common, as it isn't cold enough for ice to form.

  Temperature
• The Dorset Coast's location means that it's exposed to prevailing wind from the south-west. These prevailing winds can bring storms to the UK from the Atlantic Ocean, which bring high-energy, destructive waves which increase erosion of the coast.

  Hydraulic action and abrasion both increase during a storm and erode the base of the cliffs, making them unstable. This increases the chance of mass movement.


  Wind
• The Dorset Coast receives relatively low amounts of annual rainfall, but can experience very wet winters, with rainfall heaviest during storm periods.

  Soil and rocks become heavier when saturated, which increases the chance of mass movement.

  In January 2016, intense rainfall combined with high-energy waves during Storm Frank caused the collapse of cliffs between Burton Bradstock and West Bay.


  Rainfall
• The coastline is made from bands of hard and soft rock, which erode at different rates (create landforms eg Lulworth Cove.) Soft rock like sandstone and clay are easily eroded by hydraulic action and abrasion, whereas the harder chalk and limestone cliffs are weathered and eroded slower (stick out as headlands.) They are also susceptible to erosion by solution, where the seawater chemically dissolves the rock.


  Geology
• Lots of rain makes chalk and limestone vulnerable to carbonation weathering, as rainwater is slightly acidic.

  Prolonged heavy rain makes clay heavier, softer and more slippery, which makes mass movement more likely. During the winter, when there's more rainfall, there are often slides or slumps on the clay cliffs.

  Interactions
• sea walls

  beach replenishment

  groynes

  sea defenses
• Swanage Beach

  Stops waves and sediment- reflects them

  Protects cliffs and coastal flooding. Effective and durable.

  Creates strong backwash- removes sediment from beach and erodes under wall.

  Lack of cliff erosion means no new sediment for beach- gradually lowers the level.

  sea walls
• Swanage Beach (in winter 2005 and 2006)

  Sand and shingle dredged from sea bed at Poole Harbour and added to upper parts of Swanage beach.

  Wider beaches slow waves.

  Protects cliffs and coastal properties from erosion - looks natural

  Very expensive- £5 million to replenish beach, needs redoing ever 20 years

  Also, it threatens certian organisms that live on the sea bed.

  beach replenishment
• Swanage Beach had timber groynes built from 2005-6

  Stone/wooden fences built at right angles to the coast.

  Blocks longshore drift and traps sediment- maintains WIDE beach fo slow down waves, reducing erosion and flooding.

  Stops movement of beach, tourism, beach protects cliffs, cheap and simple.

  Rot, can be buried, bad erosion downdrift due to narrower beaches (waves arent slowed down, so more erosion and flooding)


  groynes
• industry

  tourism

  quarrying

  human land use
• Up until 1960s, gravel removed from Chesil Beach for use in the construction industry. Material was removed quicker than it was replenished, which begun to damage the landscape. This has stopped.


  industry
• Quarrying for limestone- there are many quarries on the Isle of Portland and to the west of Chesil Beach. They expose large areas of rock, making them vulnerable to chemical weathering and erosion.

  quarrying
• Attracts thousands of tourists a year. Coastal footpaths run along clifftops and tourists walking on them wear them down gradually.

  Vegetation is trampled and worn away by repeated footpath use, exposing the underlying soil and rock to weathering and erosion by wind and rain.

  tourism
• Stack and stump in Dorset coast?

  • Old Harry (stack) and his wife(stump)
• Headlands and bays in Dorset Coast?

  Swanage Bay
• Spit and tombolo?

  Hurst Spit
• Beach on Dorset coast?

  Durdle Door beach
• Why protect Dorset Coast?

  • Three national reserves - Heritage coast, AONB, SSSIs and RSPB
  • hotspot for dishing
  • luxury yachts built here
  • 140,000 people live in pool
  • Juarassic coast- important discoveries
  • Tourism - 1.1 million people a year and spent £107 million