COASTS Flashcards
What is the wave crest
The highest point of the wave
What is the wave trough
The lowest point of the wave
Features of a constructive wave?
Low frequency
Long wavelength
Strong swash
Weak backwash
Created in calm weather
Features of a destructive wave
Created from storms
Powerful
Strong backwash, weak swash
Created steeper beaches
Shingle beaches
High frequency
What 3 factors affect wave energy
Strength of the wind
Duration of the wind
Size of the fetch
What factors affect the rate of erosion
Waves
Beach size
Rock faults
Rock lithology
What are the processes of transportation
Traction
Saltation
Suspension
Solution
Examples of mechanical (physical) weathering
Freeze thaw
Salt crystallisation
Wetting and drying
Examples of chemical weathering
Carbonation
Oxidation
Solution
Biological weathering
Plant roots
Birds
Rock boring
Seaweed acids
Decaying vegetation
Examples of mass movement
Soil creep
Mudflows
Rockfall
Landslides
Runoff
How do spits occur
When the coast changes direction.
Longshore drift deposits the material
Sea changes in wind direction. Leads to a curved end of the spit.
How are barrier beaches created
When a beach or spit is extended across to a bay
Traps water from the lagoon
Separated from the mainland
Common in areas of low tidal range
How are tombolos created
Bar or beach that connects the mainland to an offshore island
Due too wave refraction
What is isostatic change
Occurs when land rises or falls close to the sea.
Localised change.
What is ecstatic change
Affects sea level across the whole planet.
Due to thermal expansion or changes in glacial processes.
What are groynes
Timber or rock that trap sediment from LSD
Help to build up the beach
Increase tourist potential
Visually unappealing
Increases erosion elsewhere
Sea walls
Concrete structures
Absorb and reflect wave energy
What is abrasion
A form of erosion
Where loose material ‘sandpapers’ the walls and floors of the river, cliff or glacier
What is coastal recession
The retreat of a coastline due to erosion, sea-level rise or submergence
What us eustatic
Global changes to sea level
What is freeze thaw
Water freezes in the cracks of a rock, expands and enlarges the crack, this weakens the rock.
Type of physical sub-aerial weathering
What is geology
The structure and arrangement of a rock
What does impermeable mean
Rock that does not allow rainwater to pass through
Isostatic
Change in local coastline or land height relative to the sea level
Permeable
Rock that allows rainwater to pass through it
Submergent coast
Coast that is sinking relative to the sea level of the time
What is a sediment cell
Areas along the coastline where the movement of material is largely self-contained.
Closed coastal sub-system.
How are tides caused
Gravitational pull of the sun and moon
Happens twice a day
Features of a constructive wave
Deposit material
Build gently sloping beaches
Created in calm weather
Strong smash, weak backwash
Low frequency
Long wavelength
Low in height
Upper beach marked by ridges, berms
Features of a destructive wave
Created form distant storms
Powerful high energy
Long fetch
Strong backwash, weak swash
What is a high energy coastline
Strong prevailing winds lead to high energy waves with greater erosion than deposition
What is a low energy coastline
Low energy waves, deposition exceeds erosion rate
What are sediment cells
Areas along the coastline where sediment is recycled within themselves, and therefore considered closed systems.
Distant areas of coastline separated by headlands
What do sediment cells help with
Help define coastal processes as a system.
Assists in shoreline management plans.
Identifies the links between inputs, components, stores, transfers and outputs
What is a SMP
Shoreline Management plan
What is a sediment budget
Balance between changes in the volume of sediment held within the system and the volume of sediment entering or leaving the system
What is a positive budget
More inputs than outputs to the system
What is a negative budget
Outputs are higher than the inputs to a system.
Explain Flamborough Head
Made of chalk- a resistant sedentary rock
Layers of chalk are visible and roughly horizontal
Vertical cracks run through the chalk
Sea is eroding the chalk causing frequent rockfall.
