geography AS coasts

what are the characteristics of a constructive wave

low frequency // low and long // powerful swash // carries material up the beach and deposits it

1 of 51

what are the characteristics of a destructive wave

high frequency // high and steep // weak swash // strong backwash // removes sediment from the beach

2 of 51

what are the 5 ways that waves erode the coastline

abrasion //hydraulic action // attrition // corrosion (solution) // quarrying

3 of 51

what is abrasion

bits of rock and sediment carried by the waves smash against the cliff and break sediment off

4 of 51

what is hydraulic action

air crack in the cliff are compressed when waves hit it and the pressure breaks of pieces of sediment

5 of 51

what is quarrying

the energy of the waves as it breaks against the cliff is enough to detach bits of rock

6 of 51

what is corrosion / solution

soluble rocks get gradually dissolved by the sea water

7 of 51

what is attrition

rocks in the water smash against each other breaking them down into smaller rocks and smooting them off

8 of 51

what factors affect the rate of erosion along the coastline

the width of the beach // the breaking point of the waves / the aspect // the fetch of the waves // the rock type

9 of 51

how are cliffs and wave cut platforms formed

over time cliffs retreat due to waves and weathering / erosion causes a notch to form the high water mark which develops into a cave / the rock above is unstable and collapses / the flat surface left is the wave cut platform

10 of 51

how are headlands and bays formed

form where there are bands of alternating hard and soft rock at a right angle to the shoreline / the soft rock is eroded quicker than the hard rock so the hard rock sticks out causing a headline and a space where the soft rock retreats is the bay

11 of 51

how is a cave arch stack and stump formed

weak areas are eroded to form caves / the roof of the cave is weakened at certain points causing a blow hole through the roof / erosion will continue to form an arch which collapses to form a stack / this is eroded forming a stump

12 of 51

how is a beach formed

when constructive waves deposit sediment on the shore

13 of 51

what is the difference between sand and shingle beaches

shingle beaches are steeper and narrower made with larger sediment

14 of 51

how is a spit formed

form where there is a sudden change in the coastline's direction // long shore drift continues to deposit material leaving a bank of sediment in the sea / changes in the wind direction may lead to curved ends / the area behind may become a marsh

15 of 51

how are bars formed

form when there is a sudden change in the direction on the coast but longshore drift continues to move sediment in the same direction so two headlands are connected and a lagoon forms behind the bar

16 of 51

how are sand dunes formed

formed when sand is moved up the beach by the wind and trapped by driftwood and plants / grass so more sand accumulates there creating and embryo dune. overtime older ones migrate inland as new embryo genes are made

17 of 51

how are saltmarshes formed

formed in areas of sheltered water as silt and mud are deposited by the river mudflats develop. the mudflats are colonised by vegetation, the plants trap more mud and silt .

18 of 51

social impacts of the eroding holderness coastline

property prices of houses at risk or erosion has fallen dramatically / around 30 villages have been lost since roman times / increased stress for villages near the coastline

19 of 51

economic impacts of the eroding holderness coastline

visitor numbers in bridlington have dropped by 30% / ulrome caravan park looses around 10 spaces a year / £2 million has been spent at Mappleton to prtect the coastline / 80,000m squared of farmland is lost a year

20 of 51

environmental impacts of the eroding holdreness coastline

Some SSSis are at risk

21 of 51

reasons for the eroding holdreness coastline

long fetch / narrow beaches / easily eroded rock type

22 of 51

what is eustatic sea level change

sea level change caused by a change in the volume of water in the sea or a change in the shape of the ocean basin

23 of 51

what is isostatic sea level change

sea level change caused by vertical movements of the land relative to the sea

24 of 51

how are ria formed

where river valleys are partially submerged. they have gentle long and cross profiles. they are wide and deep at the mouth becoming narrower and shallower inland

25 of 51

how are fjords formed

formed when a glacial valley if submerged they are relatively straight and narrow with very deep sides. shallow mouth caused by the threshold formed by deposition they are deep further inland

26 of 51

what are the social impacts of the boxing day tsunami

230,000 people killed or missing // 1.7 million made homeless // most drinking water was polluted // 400,000 jobs lost is sri lanka alone

27 of 51

economic effects of the boxing day tsunami

$8-15 billion worth of damage // most fisshing boast and equipment was destroyed along the coasts // tourism dropped rapidly due to damaged hotels and fear

28 of 51

environmental impacts of the boxing day tsunami

8 million litres of oil were released into the environment // mangrove forests were damaged by the waters force

29 of 51

how did human activity increase flooding in the boxing day tsunami

destruction of mangroves forests lead to lack of protection // illegal coral mining reduced natural protection

30 of 51

what are the 4 options for coastal management

hold the line // advance the line // managed retreat // do nothing

31 of 51

what is a sea wall

an large concrete wall that reflects the waves back out to sea preventing erosion of the coastline

32 of 51

disadvantages of a sea wall

very expensive (£2000 a metre) // obstructive and unnatural // high maintenance costs // creates strong backwash

33 of 51

advantages of a sea wall

barrier to protect against flooding // very effective in stopping erosion // act as a tourist attraction // lasts for a long time

34 of 51

what is a revetment

a slanted structure built at the foot of the cliff that absorbs the waves energy as they break against it to reduces cliff erosion

35 of 51

advantages of revetments

cheap to maintain // reduce coastal erosion

36 of 51

disadvantage of revetments

expensive // create strong backwash // unnatural

37 of 51

what is a gabion

rock filled cages at the foot of the cliff that absorb the waves energy to reduce erosion

38 of 51

advantages of gabions

cheapest hard engineering method (£100 per metre) // reduce erosion

39 of 51

disadvantages of gabions

not very strong // ugly

40 of 51

what is rip rap

boulders piled up along the coastline that absorb the waves energy

41 of 51

advantages of rip rap

fairly cheap // not a unnatural as others

42 of 51

disadvantages of rip rap

can move in a storm

43 of 51

what is a groyne

fences built at right angles to the coastline that trap beach sediment moved by LSD creating a wider beach increasing protection

44 of 51

advantages of gryones

create wider beaches / increase tourist potentials

45 of 51

disadvantages of groynes

starve beaches downdrift leading to more erosion there // unnatural

46 of 51

what is beach nourishment

when sand and shingle are added to the beach from elsewhere to create wider beaches

47 of 51

what is beach stabilisation

reducing the slop angle by planting vegetation to stabilise the sand creating a wider beach

48 of 51

what is dune regeneration

where sand dunes are created and restored by nourishment or stabilisation to provide a barrier

49 of 51

strategies along the holderness coastline

4.7km long sea wall and groynes at Bridlington / sea wall groynes and rip rap at hornsea and withernsea // revetment to protect easington gas terminal / gabions at hornsea caravan park // mappleton has 2 rock groynes and a long revetment costing £2 m

50 of 51

strategies at Blackwater Estuary

breach of seawall in 1995 and 40 hectros flooded at oapland / breach of sea wall and 21 hectres flooded and lower wall built at tilsbury / beach nourishment at mercy island / march stabalisation by planting stakes at ray creek

51 of 51

Get Revising

geography AS coasts

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Similar Geography resources:

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Related discussions on The Student Room

Similar Geography resources: