Studied by 5 people
What is it?
hard engineering, hard material like concrete to sea
Benefits
prevents erosion
prevents flooding acting as a barrier
Cons
expensive to build + manufacture
creates a strong backwash eroding under the wall
Low frequency being low + long
Swash is more powerful than backwash, so material is deposited
High frequency being high + steep
Backwash (moving down the beach) is more powerful than their swash (water moving up the beach) so material is removed
[happens when temperature alternates above/below 0°C]
water enters cracks in rock e.g. granite
water freezes + expands putting pressure on the rock
water thaws contracting releasing pressure on the rock
repeated freezing and thawing widens cracks and breaks the rock up
Rainwater has CO2 dissolved in it making a weak carbonic acid
carbonic acid reacts with the rock containing calcium carbonate e.g. carboniferous limestone which is a rock dissolved by rock
SLIDES
material shifts in a straight line along a slide plane
SLUMPS
material rotates along a curved slip plane creating a scarps
ROCKFALLS
material breaks up, often along bedding planes falling down the slope
Waves follow the direction of the prevailing wind (most common)
Hits the coast at an oblique angle (not a right-angle)
Swash carries material up the beach in the same direction as the waves
Backwash carries material down the beach at right angles, back towards the sea
Material zigzags along the coast
When there's lots of erosion somewhere else so there is more material available
lots of material is transported into the area
power of the water
size of the particles
resistant rock makes up headlands but has cracks
waves crash into headlands enlarging cracks (by hydraulic power + abrasion)
repeated erosion and enlarging cracks forms a cave
continued erosion deepens cave until it breaks through forming an arch (e.g. Durdle Door, Dorset)
erosion continues to wear rock away and eventually collapses
forms a stack, a separate rock from the headland e.g. Old Harry in Dorset
waves cause erosion at the foot of a cliff, forming a wave-cut notch enlarged over time
repeated erosion causes rock above notch to become unstable and collapse
collapsed material is washed away + cycle repeats
after repeated collapsing, cliff retreats leaving a wave-cut platform e.g. Southerndown, South Wales
spits form at sharp bends in the coastline e.g. at a river mouth
long-shore drift transports sand and shingle past the bend and deposits it in the sea
strong winds + waves curves end of the spit
area behind spit is sheltered from waves, so material accumulates and plants are able to grow
the sheltered area becomes mud flat or a salt marsh e.g. Welwick Saltmarsh, Yorkshire
a bar forms when a spit joins two headlands together
the bay between the headlands gets cut off from the sea
means a lagoon can form behind the bar
offshore bars can form if the coast has a gentle slope - friction with sea bed causes waves to slow down and deposit sediment offshore, creating a bar not connected to the coast
Sand dunes (e.g. Camber Sands, East Sussex) are formed when sand deposited by long-shore drift is moved up the beach by the wind
obstacles decrease cause wind speed so sand is deposited, forming small embryo dunes
embryo dunes are colonised by plants & the roots of the vegetation stabilise the sand, encouraging more sand to accumulate there forming fore-dunes and eventually mature dunes and new embryo dunes form in front of stabilised dunes
dune stacks (small pools) can form in hollows between dunes
Caves, Arches and Stacks
caves + arches cannot be found on a map
stacks look like little blobs in the sea
Cliffs and Wave- cut Platforms
cliffs are shown on maps as little black lines
Wave-cut Platforms are shown as bumpy edges along the coast
Beaches
sand beaches are shown on maps as a pale yellow
shingle beaches are shown as white or yellow with speckles
Spits
shown by a beach that carries on out to sea but is still attached to land, there may be a sharp bend in the coast
Durdle Door
example of an arch formed on a concordant coastline
after the band of limestone was eroded the bands of softer rock behind this eroded quickly, the remaining limestone was a headland. Wave action opened up a crack in the side of headland which developed into an arch
What is it?
hard engineering, wall of wire cages filled with rocks built at the foot of cliffs
Benefits
absorbs wave energy reducing erosion
cheap + easy to build
Cons
ugly
wire cages corrode over time
What is it?
hard engineering, boulders piled up along the coast
Benefits
absorbs wave energy reducing erosion + flooding
fairly cheap defence
Cons
boulders can be moved around by strong waves so they need to be replaced
What is it?
hard engineering, wooden/stone fences are built at right angles to the coast trapping material transported by long-shore drift
Benefits
creates wider beaches slowing down the waves
gives greater protection from flooding + erosion
fairly cheap defence
Cons
starves beaches further down the coast of sand, making them more narrow
narrow beaches don't protect the coast very well so this leads to erosion
What is it?
soft engineering, sand and shingle from elsewhere is added to the upper parts of the beach
Benefits
creates wider beaches slowing down the waves
gives greater protection from flooding + erosion
Cons
taking material from seabed kills organisms like sponges + corals
very expensive
has to be repeated
What is it?
soft engineering, creating/restoring sand dunes by nourishment or by plant vegetation to stabilise the sand
Benefits
creates a barrier between land and sea absorbing wave energy, preventing flooding and erosion
stabilisation is cheap
Cons
limited to small area
nourishment is expensive
Over time the land will become marshland, which protects the land behind it from flooding + erosion
Cheap and easy strategy + no maintenance
Creates new habitats for plants and animals
However flooding farmland affects livelihood of farmers and saltwater can have a negative effect on existing ecosystems
![<p>[happens when temperature alternates above/below 0°C]</p><ol><li><p>water enters cracks in rock e.g. granite</p></li><li><p>water freezes + expands putting pressure on the rock</p></li><li><p>water thaws contracting releasing pressure on the rock</p></li><li><p>repeated freezing and thawing widens cracks and breaks the rock up</p></li></ol>](https://knowt-user-attachments.s3.amazonaws.com/356b8743f9594806b796e27e650459d0.png)
![Large particles like boulders are pushed along the river bed by the force of the water [IMAGINE TRACTOR WHEELS]](https://knowt-user-attachments.s3.amazonaws.com/87a404f168904ef18175f27225c4f35f.png)
