UK Physical Landscape: Coasts Flashcards
Relief
Physical features of landscapes (steepness, height above sea level)
Fetch
The distance over which wind has blown
Constructive Waves
Build a beach
Strong swash
Wave crests far apart
Destructive Waves
Destroy a beach
Strong backwash
Wave crest close together
Mechanical Weathering
The breaking of rocks at the base of the cliff
Chemical Weathering
Acidic rainwater dissolving rock
Biological Weathering
Plant roots grow into rocks, animals burrow into rocks
Rockfall
Fragments of rock break away from cliff face
Landslide
Blocks of rocks slide downhill
Mud flow
Saturated soil and weak rock flows down a slope
Rotational slip
Saturated soil and weak rock flow along a curved surface
Hydraulic action
Power of waves as they smash into rocks
Abrasion
Pebbles grinding over a rocky platform, making it smooth
Attrition
Rock fragments knocking against one and other, therefore smaller and rounded.
Solution (erosion)
The dissolving of soluble chemicals in rocks
Suspension
Particles suspended in water
Traction
Large pebbles rolled along the seabed
Saltation
‘Bouncing’ of particles too heavy to be suspended
Solution (transportation)
Dissolved chemicals
Long Shore Drift (LSD)
The movement of material in a zig zag motion along the coast is usually in the direction of the prevailing winds.
Headlands
Formed on dis-concordant coastlines. Hard rock cannot be worn away leaving hard rock sticking out.
Bays
Formed on dis-concordant coastlines. Destructive waves erode soft rock to leave an indent on cliff face
Wave-cut platform & notch
Sea attacks the base of the cliff through destructive waves, creating a wave cut notch until the cliff collapses into a wave cut platform.
Crack into stump
Lines of weakness appear and turns into cracks
The crack grows through hydraulic action and abrasion into a cave
The cave becomes an arch as undergoes undercutting
The arch’s roof collapses due to erosion and gravity creating a stack
The stack erodes and collapses creating a stump
Swanage
Located in a sheltered bay, broad sandy beach
Headlands and bays
159km of coast
Landform names and locations -
Indented coastlines (dis-concordant coastlines)
Poole Harbour
Two spits at the mouth of the harbour
Old Harry (stack)
Beach
Landform of deposition created with sand, shingle and slit
Spit
Erosion occurs further up the coastline, prevailing winds change direction causing LSD, the river mouth stops spit from growing
Bar
When ridges of sand stretch from one bay to another, forming a lagoon behind it
Sand dunes
Small hills behind the beach, to form there must be a good supply of dry sand, wide and vegetation.
Sea walls - disadvantages
Expensive
Damages landscape
Sea walls - advantages
Prevents flooding
Creates a promenade
Groynes - advantages
Cheap
Builds up beach
Counteracts LSD
Groynes - disadvantages
Starve other places of sand
Rock armour - advantages
Cheap
Easy to maintain
Used for fishing
Rock armour - disadvantages
Expensive to transport materials
Obtrusive
Gabions - advantages
Cheap to produce
Merge with landscape
Improve drainage of cliffs
Gabions - disadvantages
Looks unattractive
Only lasts 5 - 10 years
Beach nourishment - disadvantages
Needs maintenance unless structures are built
Beach nourishment - advantages
Cheap
Blends in with the beach
Increases tourism
Dune regeneration - advantages
Coastal environment is maintained
Cheap
Dune regeneration - disadvantages
Time consuming to plant marram grass
Can be damaged by storms
Dune fencing - advantages
Can control access to other ecosystems
Dune fencing - disadvantages
Unsightly
Maintenance needed after storms
Lyme Regis
Phase 1 - new sea walls and promenades
Phase 2 - new sea walls, promenades and a creation of a wide beach
Phase 3 - not undertaken (costs outweighed the benefits)
Phase 4 - new 390m sea wall in front of the existing sea wall
