Coasts Flashcards
Give 3 factors of wave energy
Distance wind has been blowing
Wind speed
Time wind has been blowing
Give 4 qualities of constructive waves
Low energy
Deposition
Backwash < swash
Small fetch
Give 4 qualities of destructive waves
High energy
Erosion
Backwash > swash
Large fetch
Name the 4 types of erosion and what they are
Hydraulic Action - wave power breaks rock
Abrasion - Material rubs against cliff
Attrition - Waves break up material
Solution - Acidic water dissolves chalk/limestone
Name 4 types of transport and what they are
Solution - cliff minerals dissolved
Suspension - currents carry small pieces
Saltation - load bounded along sea level
Traction - large sediment rolled along sea bed
Name 4 coastal landforms (not stack) and how they are formed
Beaches - constructive waves build up beaches
Wave-cut platforms:
- Weather weakens clifftop
- Sea strands base -> wave cut notch
- Notch gets bigger -> collapse
- Backwash moves rubble -> sea
Spits:
- Extended stretch of deposited material
- Formed by longshore drift at prevailing wind direction on coastline
- Spit grows, kept there by plant roots
- Waves can’t get past it - silt deposits in sheltered ares -> salt marsh
Headlands and Bays:
- Hard rock resistant to erosion - left jutting out -> headlands
- Soft rock easy to erode -> bays
Explain how a stump is formed, step by step
- Cliff undergoes hydraulic action -> crack -> cave
- Cave erodes further -> arch
- Top of arch collapses -> stack
- Stack erodes -> stump
Give 3 factors of cliff recession
Larger fetch = larger waves
Slowed down by sea defences
Hard rock erodes slower
Name 3 human impacts of cliff recession
Property loss
Low house prices
Hard to get insurance
Give 1 natural impact of cliff recession
Habitat destruction
Give 4 causes of coastal flooding
High tides
Rising sea levels
Strong, stormy waves
Storm surges
Give 1 way coastal flooding can be reduced through prediction
Environment Agency monitors sea conditions
Give 4 ways coastal flooding can be reduced through planning
Early warning system
Flood education
Escape routes
Advice from Health Protection Agency
Give 3 ways coastal flooding can be reduced through prevention
Flood barriers
Open space on flood plains to absorb water
Name 4 examples of hard engineering sea defences, and the advantages of disadvantages of them
Sea Wall (Hornsea):
Ad: Protects cliff and buildings
Dis: Expensive (£10k/m2)
Groynes (Hornsea):
Ad: Stops longshore drift
Dis: Exposes other areas
Rip Rap:
Ad: Absorbs energy cheaply
Dis: Hard to transport
Offshore Reef (Bournemouth): Ad: Waves break on reef, loses power Dis: Expensive, messes with boats
Name 2 examples of soft engineering sea defences, and the advantages of disadvantages of them
Beach replenishment:
Ads: Cheaply reduces wave power
Dis: Sand imported from somewhere else
Managed Retreat:
Ads: Damage reduced
Dis: Expensive - compensation
Explain 2 reasons why there needs to be costal management on the Holderness Coast
Strong prevailing wind create longshore drift moves material south
Soft boulder clay cliffs erode quickly
Explain 4 impacts of the £2 mil 1991 Mappleton protection scheme
Rip Rap along base of cliff
2 groynes stop longshore drift
Mappleton no longer at great risk from erosion
Increased erosion south of Mappleton
Describe how a bar is formed
- Longshore drift forms a spit
- Spit extends across bay, until it reaches other side -> bar
- Lagoon can form behind bar when it covers bay
Define weathering and the 3 types of it
Weathering:
- Weathering is the breakdown of material, due to changes in the weather causing the rocks to be broken down over time
Freeze thaw happens when there are changes in
the weather above and below zero degrees -> rock joints to expand and break off (water expands when frozen)
- Exfoliation caused bywarming and cooling of temperature -> rock peel off in layers
- Salt crystallisation = salt gets into the cracks in rocks, expands putting pressure on rock joints
Define weathering and the 3 types of it
Weathering:
- Weathering is the breakdown of material, due to changes in the weather causing the rocks to be broken down over time
Freeze thaw happens when there are changes in
the weather above and below zero degrees -> rock joints to expand and break off (water expands when frozen)
- Exfoliation caused bywarming and cooling of temperature -> rock peel off in layers
- Salt crystallisation = salt gets into the cracks in rocks, expands putting pressure on rock joints