coasts Flashcards
arch
a large cave that has gone all the way through the cliff.
abrasion
when rocks hit the cliff causing it to erode.
attrition
when rocks hit each other, grinding each other down making it into smaller, rounder rocks.
backwash
when the waves are pulled away from the sea bed. This comes from destructive waves and the stronger it is the more of the seabed is eroded and sediment is carried away.
bay
a semicircle hollowed out from a cliff. It is the result of abrasion and hydraulic action. There can often be a beach formed by attrition.
corrosion/solution
the process of chemical erosion
erosion
the wearing away of materials. Erosion can occur by hydraulic action, abrasion. attrition and corrosion/solution
headland
a coastal landform that juts out into the sea and causes
estuary
a partially enclosed body of water where freshwater from a river meets saltwater from the sea.
headland
a costal landform that juts out into the sea.
hydraulic action
the sheer force of water against the cliff
longshore drift
the movement of sediment along the coast caused by waves. It goes with the prevailing wind.
saltation
when rocks are bounced along the sea bed.
solution
when load is dissolved in the seawater
swash
when waves are pushed towards the coast. This is at the angle of the prevailing wind. It is mainly caused by constructive waves and leads to deposition of load.
spit
a narrow coastal landform that is connected to the cliff at one end. It is formed by longshore drift.
suspension
when pebbles are carried by the waves.
weathering
the breaking down of materials in situ. Can be caused by physical, biological or chemical.
traction
when boulders are rolled along the sea bed.
physical weathering
when rocks are broken down by waves, rain, wind and cold in situ.
biological weathering
when animals and plants break down rocks in situ
chemical weathering
when acids bread down rocks in situ. Such as acid rain.
destructive wave
they have a weak swash and strong backwash and a re high energy. They displace more sediment than they deposit and create sloping beaches.
constructive waves
they are low energy and have a stronger swash than backwash. They deposit more sediment than they displace.
tombolo
a spit that reaches out to an island making something not similar to a peninsula.
bar
when a spit goes across a bay creating a closed area of shallow water called a lagoon.
lagoon
a bay that has been cut off from the ocean by a bar.
hard engineering
when artificial structures are used to prevent coastal erosion
soft engineering
when the natural environment is used to prevent coastal erosion.
cave
a large crack in the rock leading.
stack
when the top of an arch is weathered and falls down, what is left is a stump.
stump
when a stack is further weathered to be very short.
beach nourishment
Large amounts of sand are added
to beaches to build them up and help absorb wave
energy. Protects tourism & the coast, is easy to carry
out and fairly cheap. But it does not last very long as
sand will continue to be transported along the coast by longshore drift
managed retreat
This allows the natural erosional
processes of the sea to occur, areas of low value land are allowed to flood hopefully protecting more
important areas further down the coast.
cliff stabilisation
Cliffs are covered in matting and
vegetation planted to help make them more stable and
resistant to erosion.
managed retreat
doing nothing. takes money away from tourism. Doesn’t let beaches look as good.
gabions
Cages of wire filled with rocks to absorb the waves energy, they are effective and cheap but environmentally ugly.
sea wall
Placed at the base of a cliff to reflect the waves energy.
Very expensive approximately £10,000 per km, ugly but extremely effective at protecting areas from flooding.
groynes
Wood or rock long vertical structures placed at right angles to the beach to trap sediment. Build up the beach and protects the cliffs from erosion but can result in areas further down the coast being starved of beach material resulting in more erosion! Only last 25-30 years.
rock armour/rip rap
Large rocks placed at the bottom of the cliff to absorb wave energy, they are effective at dispersing the waves energy and cheap but are ugly.
