Coastal Landscapes in the UK Flashcards
All 48 cards in this deck
Give three characteristics of a destructive wave.
High and steep, short wavelength (high frequency), strong backwash and weak swash.
Give three characteristics of a constructive wave.
Low in height, long wavelength (low frequency), strong swash and weak backwash.
Which type of wave builds up a beach, and why?
Constructive waves – their swash is stronger than their backwash, so material is deposited.
What is freeze–thaw (frost shattering) weathering?
Water seeps into cracks, freezes and expands, eventually breaking the rock apart.
What is carbonation (solution) weathering?
Dissolved carbon dioxide in rainwater forms carbonic acid, which reacts with minerals in rocks.
Name the three types of mass movement affecting cliffs in AQA's specification.
Sliding (landslip), slumping and rockfall.
What is slumping?
Saturated soft rock (e.g. boulder clay) moves downwards along a curved slip surface, leaving a rotated, curved cliff face.
True or false? Weathering and mass movement are the same process.
False. Weathering is the breakdown of rock in situ; mass movement is the downhill movement of material under gravity.
What is hydraulic power (hydraulic action) at the coast?
The power of waves smashing onto a cliff; trapped air is forced into holes and cracks, eventually breaking the rock apart.
What is abrasion (corrasion) at the coast?
Fragments of rock are picked up and hurled by the sea at a cliff, wearing it away.
What is attrition?
Rock fragments carried by the sea knock against each other, becoming smaller, smoother and rounder.
What is longshore drift?
The zigzag movement of sediment along a coast: swash carries material up the beach at an oblique angle, backwash returns it at right angles.
Give two reasons why sediment is deposited in coastal areas.
The flow of water slows down (e.g. in sheltered bays or where the coast changes direction), or friction with a gently sloping seabed reduces wave energy.
True or false? The direction of longshore drift is determined by the direction of the prevailing wind.
True. Waves follow the prevailing wind and hit the coast at an oblique angle, moving material in that direction.
Why do headlands and bays form along a discordant coastline?
Softer, less resistant rock is eroded more quickly to form bays; harder, more resistant rock is left jutting out as headlands.
What does wave refraction do to wave energy around a headland?
It focuses (concentrates) wave energy on the headland and spreads it out in the bays.
What is a wave-cut platform, and how is it left behind?
A flat rocky surface at the base of a cliff, left as a wave-cut notch undercuts the cliff, which collapses and retreats.
Which landform is left when the roof of an arch collapses, and what does it become later?
A stack; continued erosion makes it collapse into a stump.
True or false? Chalk cliffs are eroded faster than boulder clay cliffs.
False. Chalk is harder/more resistant, so it is eroded more slowly; soft boulder clay erodes rapidly.
Where on a bay does a beach usually form, and why?
At the head (innermost part) of the bay, where wave action is weakest so deposition occurs.
What is a spit?
A sand or shingle beach joined to the land at one end but projecting out (downdrift) into the sea, often with a recurved end.
Where do spits begin to form?
Where the coastline suddenly changes shape or at a river mouth/estuary, with material building up in the sheltered lee.
What is a bar?
A ridge of deposited material that grows right across a bay by longshore drift, often trapping a freshwater lagoon behind it.
True or false? A spit grows all the way across a river estuary.
False. River currents carry material seaward, so the spit cannot grow right across the estuary.
What is a sea wall?
A concrete or stone barrier at the foot of cliffs or the top of a beach that deflects wave energy back out to sea.
Give one benefit and one cost of a sea wall.
Benefit: it protects cliffs from erosion and prevents flooding, and often carries a promenade. Cost: very expensive to build and maintain.
What is rock armour (rip rap), and give one cost of it.
Large boulders placed at the foot of a cliff or wall to disperse wave energy; it looks unattractive and makes beach access difficult.
What are gabions, and give one benefit of them.
Wire cages filled with rocks placed at the base of a cliff; they are cheap, quick to build and can improve cliff drainage.
What are groynes, and what is their main disadvantage?
Wooden or rock barriers built out to sea to trap sediment and widen the beach; they starve beaches downdrift of material, increasing erosion there.
What is beach nourishment?
Adding sand or shingle from elsewhere to build up an existing beach as a natural defence against erosion and flooding.
Give one cost of beach nourishment.
It needs constant maintenance to replace material washed away, especially after winter storms.
What is dune regeneration, and give one benefit of it.
Planting marram grass and fencing to rebuild sand dunes; the dunes absorb wave energy and increase biodiversity.
What does 'managed retreat' (coastal realignment) mean?
Allowing the sea to flood or erode an area of low-value land.
Give one benefit of managed retreat.
The salt marsh created provides a habitat for wildlife and stores water, acting as a buffer against erosion — and it is cheap.
True or false? Beach reprofiling means removing a beach entirely.
False. Reprofiling moves beach material from the lower beach back up to the upper beach, usually after storms.
Give two typical reasons for managing a stretch of UK coastline.
To protect homes, businesses and roads from erosion, and to protect the local economy (e.g. tourism, farmland, harbours).
Give one positive and one negative effect of a UK coastal management scheme.
Positive: settlements and roads are no longer at risk and a wider beach forms. Negative: defences spoil the natural landscape and interfere with longshore drift, increasing erosion further along the coast.
How do sand dunes form?
Onshore winds carry dry sand inland from the beach. An obstacle (such as a plant or debris) slows the wind so the sand is dropped and piles up. Plants like marram grass then grow on it, binding the sand so the dune grows.
Why are shingle beaches steeper and narrower than sand beaches?
Swash soaks into the gaps between large pebbles, so the backwash is weak and leaves them piled up in a steep bank. Sand is fine and stays wet, so the backwash runs off it and drags grains back down, spreading a wide, gentle beach.
How does a cave on a headland become an arch?
Waves keep eroding the cave (mainly by hydraulic power and abrasion) until it cuts right through the headland, often meeting a cave on the other side, leaving an arch.
How does rock type affect the shape of a cliff?
Resistant (hard) rock forms steep, near-vertical cliffs; weak (soft) rock forms gentler, sloping cliffs.
What is the difference between mechanical and chemical weathering?
Mechanical weathering breaks rock into pieces without changing what it is made of; chemical weathering breaks rock down by changing its chemical composition.
What is a rockfall?
Pieces of rock break away from a steep cliff face and drop down to its base under gravity, often after weathering has loosened them.
What is sliding (a landslide) at the coast?
A block of rock or soil moves rapidly downslope in one piece along a flat (straight) slip plane.
What is the difference between hard and soft engineering at the coast?
Hard engineering builds artificial structures to stop or control the sea; soft engineering works with natural processes (e.g. beaches and dunes) to reduce erosion and flooding.
Give one cost of gabions.
Any one of: they look unattractive, or the wire cages rust and break over time so they don't last long.
Give one cost of managed retreat.
Any one of: land such as farmland or buildings is lost to the sea; owners lose income or homes, causing conflict; flooding with seawater can damage existing freshwater habitats.
How can you recognise a spit on an OS map?
A narrow strip of beach, drawn with the beach colours (yellow for sand, speckled for shingle), attached to the land at one end and stretching out across open water or an estuary mouth, usually where the coastline bends sharply.