Section C: UK physical landsacpes

the wind blows across the sea forming waves (distance wind blows- fetch)

Swash- water that rushes up the beach

backwash- water that flows back towards the sea

Constructive waves- formed by storms (far from the shore) low surging waves deposits sand and pebbles up the beach- constructing it

destructive waves- formed by storms (near the shore common in winter) high plunging waves with weak swash and strong backwash

Weathering

• mechanical- freeze thaw (freezes water in the cracks and expands causing weathering)
• chemical- acid rain dissolves rocks (limestone)

Mass movement- the downward movement of material under the influence of gravity 

• sliding- rocks slide downhill
• slumping- saturated rock slides down a curved slip plane
• rockfalls- rock breaks away
• erosion
  • hydraulic power- waves smash into cliffs trapping rocks 
  • abrasion- break waves throw sand, pebbles or boulders against the coast
  • attrition- rocks/pebbles rub together and break down
• transportation
  • longshore drift-  when the wave approaches the coast at an angle sand and gravel move along the beach in a zigzag pattern, as the sand is lighter it moves further
• deposition- water slows down the wave loses their energy

erosion:

• Headlands and bays- bays errode faster (softer rock and headlands harder rock)
• cliffs and wavecut platforms (flat rock at the base of a cliff)
• Caves, arches and stacks- when 2 caves errode it forms an arch, this then collapses to form a stack

deposition:

• beaches
• sand dunes- wind blows the sand on the beach inland
• spits- where the coastline orientation changes
• offshore bars- sediment experiences friction with a gentle sloping coast

discordant coastline (Swanage Bay and Duriston Head)- alternating bands of soft and hard rock are found on the east coastline (clay and sand- soft)

concordant coastline- the south coast is mainly formed of one type (limestone- hard)

Poole harbour (one of the UK's largest natural harbours)- deposition- the formation of 2 spits (sanbanks), lagoons, slatmarshes and sand dunes 

Foreland- white chalk cliffs and old harry stack

Hard engineering:

• sea walls- expensive but reliable (£10,000 per metre)
• rock armour- looks messy but quick to build (£3000 per metre)
• gambions- cheap and easy to build but dangerous (£500 per metre)
• groynes- widens beach (£5000 each- covers 200 metres)

Soft engineering:

• beach nourishment- widens beach (£200,000)
• beach reprofiling- improves seafront property protection but makes beach access harder (£250,000 every 2 years)
• dune regeneration- natural barrier to wind and waves but can move or errode (£2000 per metre)

reasons for management:

• Unstable cliff (erosion more rapid due to waves)
• need to reduce the threat of landslips

management stratergies:

• environment improvement scheme (1990's)
• 3 main phases
  • 1) seawall and promenade created to stabilise cliffs (1990-95 £1.4 million)
  • 2) new sea wall, promenades and widen beach (2005-07 £22 million)
  • 3) 390m of sea wall to protect homes (2010-15 £20 million)

effects and conflicts

• businesses thriving
• harbour better protected
• traffic and litter increased
• defences spoilt natural landscape