2.0 COASTS Flashcards
What is Fetch?
Distance of the wind can travel uninterrupted
Backwash
Straight down the beach due to gravity
What is swash?
Sea goes up beach at an angle due to prevailing wind
5 Properties of constructive wave
- Long wave length
- Low wave height
- Strong swash weak backwash
- Calm weather(less powerful)
- Deposit sediment on beach
5 Properties of destructive waves
- Short wave length
- High wave height
- Weak swash strong backwash
- Stormy weather (more powerful)
- Remove sediment from beach
Hydraulic Action
Crash in to cliffs and force apart
Abrasion
Throw rocks at cliff
Corrosion/solution
Acid water dissolves cliffs
Attrition
Pebbles hit each other and break down
Erosion rate of Mappleton (average)
7-10 m per year
Reason for Mappleton erosion
Winds have long fetch over North Sea so build energy
Defences at Mappleton
£2mill granite (Norwegian) rock groynes which build up the beach and protect the clay cliff base (and main road)
Ecstatic change
Where the sea level rises and land stays the same
Isostatic change
Where the land height changes
What’s beach nourishment? (+where)
Sediment from off shore sea bed in spread along the beach SEAFORD
Advantages of beach nourishment
Attracts tourists
Isn’t ugly
Stops beach sinking
Disadvantages of beach nourishment
Very expensive
Harms marine life scares animals
Heavy machinery
Needs replacing
Whats managed realignment? (+where)
Water breaks embankment and creates salt marshes and mud flats. Absorbs energy. TOLLESBURY
Advantages of managed realignment
Cheap
Sustainable
Stores water during storm surges
DisAdvantages of managed realignment
Need to remove previous defences
Land sacrifice
How is a wave created?
Wind causes friction at the surface and the energy is passed on through the water
