Section C- Physical Landscapes In The UK Flashcards
what is hydraulic action?
force of water against river bed
what is abrasion?
river throws particles against river bed at high velocity
what is attrition?
loads bumps into each other being smoothed and broken into small particles
what is solution?
chemicals in water dissolved the bed and banks
what is traction?
large material rolled along the river bed
what is saltation?
small pebbles bounce along river bed
what is suspension?
fine material carried in waters flow
what is soltuion? (transportation)
dissolving loads that are soluble in rainwater
e.g chalk and limestone
name the two types of waves
constructive
destructive
give characteristics of a constructive wave
strong swash and weak backwash 8-10 waves per minute build up beaches occur in summer under 1m long
give some characteristics of a destructive wave
over 1m very high and short weak swash and strong backwash 10-14 waves per min erodes beaches occurs in winter
what landforms form as a result of erosion?
headlands and bays
cliffs ad wave cut platforms
caves,archers,stacks,and stumps
how do headlands and bays form
alternate bands of resistant+ non resistant rock align at right angle to coast
less resistant rock eroded more quickly hydraulic action and abrasion
more resistant rock protruding into sea forming a headland
what happens to the bays that are formed once the less resistant rock has been eroded?
become low energy environments in which deposition occurs
exposed headlands becomes erosion target
beaches are built up by constructive waves
what is a headland?
a cliff promontory which juts out into the sea
what is a bay?
a crescent shaped indentation in the coastline found between two headlands
what is a cliff?
a steep or vertical face of a rock often found at a coast
what is wave cut platform?
a wide gently sloping rocky surface at the foot of the cliff
what is weathering?
Weathering is the breaking down or dissolving of rocks and minerals on Earths surface.
what is longshore drift?
Waves approach coast at angle.
Swash carries sediment up beach at an angle.
Backwash carries sediment down beach with gravity – at right angles to beach.
zig-zag movement of sediment along the beach.
how do wave cut platforms form?
destructive waves hits against cliff face causing undercutting (HA + Corrasion)
cliff face is unsupported too heavy so falls off
this sediment broken down by attrition and thrown back at the cliff by abrasion
cycle repeats leaving a platform
how do cliffs form?
weathering wears down rock
rock left behid is more resistant- typically vertical
weathering weakens top and erosion wear bottom away
what are the characteristics of a wave cut platform?
gentle slope
bare rock interspersed with rock pools
barnacles on rocks
what are the characteristics of cliffs?
horizontal bedding
layers of hard rock jutting out
verticle bare rock cliff face
how are caves,achers and stacks formed?
1) headland made of chalk and limstone natural cracks
2) sea finds cracks,erodes them wi HA+abrasion until caves
3) continues this on both sides of headland forms an arch
4) erodes the arch till roof collapses leaving stack
5) headland retreats
6) sea attacks stack causing it to weaken and fall into a stump
what are the characteristics of a sandy beach?
shallow,flat,formed by constructive waves, sand dune back of beach.long
what are the characteristics of a pebbled beach?
steep,formed y destructive waved, large pebbles at back of beach, short
how does a sandy beach form?
1) low energy constructive waves transport material into sheltered bay
2) sediment constantly moved up beach-swash stronger than backwash
how does a pebbled beach form?
1) destructive waves have stronger backwash-pebbles dont move far up beach
2) this makes a steeper beach- usually form when there is strong winds
how do sand dunes form?
1) wind blowing inland transports sand particles by saltation up the beach
2) height of sand builds up and becomes unstable
3) sand slips down the leeward slope
what is a spit?
an area of sand or shingle which either extends at a gentle angle out to see or which grows across a river estuary
How do spits form?
prevailing wind-Longshore drift move material along coastline.
spit forms when the material is deposited.
Over time,spit grows + develops a hook if wind direction changes further out.
Waves cannot get past so creates a sheltered area wherw mud flats or salt marshes form.
What is a bar?
Where a spit grows across a bay
how is a bar formed?
longshore drift continues to extend the length of the spit and forms a bar which has a lagoon behind it
which part of the UK coastline did we study to identify its main landforms?
swanage bay
where is swanage bay located?
Dorset
what features does swanage bay show?
headland (ballard point)
bay (swanage)
where can good examples of cliff erosion and wave cut platforms be found?
Flamborugh head (yorkshire)
what are hard engineering strategies?
man made structures built to control flow of sea
what are gabions?
wire mesh cages filled with small rocks+ pebbles
can be stacked to form wall like barrier at back of beach
what are the economic benefits of gabions?
£110 a meter- cheap
easy to construct
constructed on site wi local pebbles- cheaper
last 20-25 years
what are the environmental benefits of gabions?
blend in better
what are the economic costs of gabions?
restricted to sandy beach- shingle hurled at them would degrade it on pebbled beaches
expensive to repair vegitated ones
maintenance
what are the social costs of gabions?
people trip or cut themselves on wire mesh if broken
what are the environmental costs of gabions?
sea birds damage feet
damaged ones can look unsightly
what is a sea wall?
wall made out of a hard material reflects waves back into the sea
what is a groyne?
wooden or stone fences built at right angle to coast
what is rock armour?
boulders that are piled up usually at back of beacj
what are the economic benefits of sea walls?
last for many years if well maintained
what are the social benefits of sea walls?
sense of security
double as a cycle route/walk
what are the environmental benefits of sea walls?
don’t impede movement of sediment
what are the social costs of sea walls?
restrict access to beach
what are the economic costs of a sea wall?
£5,000 per linear meter-expensive+costly repairs
what are the environmental costs of sea walls?
ugly to look at
destroy habitats
what are the social benefits of groynes?
act as wind breaks
people can sit on them
what are the economic benefits of groynes?
£5,000 each- cheap
if well maintained last up to 40 yrs
what are the social costs of groynes?
stop people walking along beach
wind surfers collide wi them
what are the economic costs of groynes?
restrict supply of sediment down drift
ineffective in stormy conditions
need regular maintenance so don’t rot
what are the environmental costs of groynes?
unattractive
what are the economic benefits of rock armour?
£1000-3000 a metre
quick + easy to build
versatile
what are the social costs of rock armour?
access to beach difficult
collect slippery seaweed hazard risk
what are the economic costs of rock armour?
foreign rocks used inflates the cost
maintaining regularly as storms move rocks
what are the environmental costs of rock armour?
ugly+ covers vast areas of beach
don’t blend in with local geology
what is beach nourishment?
sand and shingle from somewhere else is added to beach
what is sand dune regeneration?
creating/restoring sand dunes either by nourishment or planting vegetation
what is beach reprofiling?
direct transfer of material from the lower to the upper beach
what are the social benefits of beach nourishment?
more room for people
people living along sea front more protected from flooding
what are the economic benefits of beach nourishment?
protects expensive properties