Coastal Landscapes

Question 1

what are waves?

Answer 1

caused by wind dragging on the surface of the water

Question 2

what is a fetch?

Answer 2

length of water the wind blows over

Question 3

what is a wave frequency?

Answer 3

number of wave crests passing a certain point

Question 4

what is the crest?

Answer 4

highest point of a wave

Question 5

what is the trough?

Answer 5

lowest point of a wave

Question 6

what is the wave length?

Answer 6

difference between two crests

Question 7

what is the wave height?

Answer 7

difference in height between the crest and trough

Question 8

what is mechanical weathering?

Answer 8

the breakdown/disintegration of rock without changing its chemical composition

Question 9

what is chemical weathering?

Answer 9

the breakdown of rocks by changing its chemical composition

Question 10

what is mass movement?

Answer 10

downward movement or sliding material, under the influence of gravity

Question 11

what is sliding or landslides?

Answer 11

blocks of rock sliding straight, downhill

Question 12

what is rock-fall?

Answer 12

fragments of rock break away from the cliff face (often due to freeze thaw)

Question 13

what is freeze-thaw process?

Answer 13

DAY - water collects in cracks of rocks
NIGHT - water freezes, expansion causes pressure and cracks are enlarged
BOTH - rock fragments break up and collect at the bottom as scree

Question 14

what is slumping?

Answer 14

rotational slip - slump of saturated soil and weak rock along a curved surface

Question 15

how can salt spray cause mechanical weathering?

Answer 15

•seawater contains salts that evaporate and leave crystals
•in cracks salt crystals grow/expand •puts pressure on the rocks
•forcing them to knock off

Question 16

where do landslides occur?

Answer 16

eroding cliffs with wet slopes

Question 17

what is hydraulic action?

Answer 17

•air cracks in cliffs are compressed when waves crash into them
•pressure is exerted and break off rock pieces

Question 18

what is corrosion?

Answer 18

soluble rocks (like limestone and chalk) gradually dissolve by seawater

Question 19

what is attrition?

Answer 19

•eroded particles smash into each other
•break into smaller fragments
•edges are rounded off and smoothed

Question 20

what is abrasion?

Answer 20

•rock and sediment are transported by the waves
•grinding against cliffs
•break bits off/smoothing surfaces

Question 21

what is a constructive wave?

Answer 21

•have a strong swash and a weak backwash
•deposition is greater than erosion

Question 22

what is a destructive wave?

Answer 22

•have a weak swash and a strong backwash
•erosion is greater than deposition

Question 23

what is the process of long shore drift?

Answer 23

1) waves follow direction of prevailing winds
2) hit the coast ‘head on’ and swash moves sediment up the beach
3) backwash carries sediment down and along the beach at right angles (causing zigzags)

Question 24

what is the process of a wave-cut platform?

Answer 24

1) erosion occurs at the foot of the cliff, forming a wave-cut notch
2) rock above becomes unstable due to weathering and the force of gravity
3) top eventually topples under its own weight, forming a wave-cut platform (which is left behind as the cliff retreats)

Question 25

what is the process of forming headlands and bays?

Answer 25

1) form where there are alternating bands of resistant and less resistant rocks types 2) less resistant rock erodes quickly, forming a bay 3) resistant rock erodes more slowly, left jutting out, forming a headland

Question 26

what is the process of forming caves, arches, stacks and stumps?

Answer 26

1) waves crash into headlands and enlarge cracks (hydraulic action and abrasion) 2) enlarged cracks form caves 3) fault lines run through the headlands and deepens the caves, forming an arch 4) through wave attack at the base and weathering on the roof, strength is weakened and collapses into a stack 5) stacks will eventually collapse to stumps, that may be covered by water in high tides

Question 27

how are beaches formed?

Answer 27

•by constructive waves, depositing either sand or shingle SAND - flat and wide, particles are small and can be moved by longshore drift SHINGLE - steep and narrow - particles are large and cannot be moved by longshore drift, create a slope

Question 28

how do spits form?

Answer 28

•form at mouths of rivers or across a bay •strong winds curve the end •stronger waves further out force sediment back towards the shore •must have constructive waves so longshore drift can occur

Question 29

how do bars form?

Answer 29

•two headlands joined together •cuts off/blocks off the bay between headland and sea •a lagoon can form - but they don’t last forever (soon filled with sediment)

Question 30

how do sand dunes form?

Answer 30

•sand is deposited by longshore drift •obstacles cause wind speed to decrease so sand is colonised by plants and grasses •forms embryo dunes

Question 31

what are groynes, what are there advantages and disadvantages?

Answer 31

•timber or rock structures that are built at right angles to trap sediment transported by longshore drift ADVANTAGES - create wider beaches, cheap DISADVANTAGES - starve beaches, making them narrower, don’t protect coast as well, leads to erosion and flooding

Question 32

what is a sea wall, and what are its advantages and disadvantages?

Answer 32

•made out of concrete or rock that reflects waves back to the sea ADVANTAGES - prevents erosion, barrier to prevent flooding DISADVANTAGES - expensive to build and maintain, look unattractive

Question 33

what is rock armour and what are its advantages and disadvantages?

Answer 33

•boulders piled up to absorb waves energy ADVANTAGES - reduce erosion and flooding, cheap DISADVANTAGES - boulders can be moved by strong waves so need to be replaced, expensive to transport from other areas, do not fit with geology

Question 34

what are gabions and what are it advantages and disadvantages?

Answer 34

•wire cages filled with rocks ADVANTAGES - cheap, absorbs waves energy, reduce erosion, easy to build DISADVANTAGES - unattractive, cages rust

Question 35

what is beach nourishment and what are its advantages and disadvantages?

Answer 35

•addition of sand or shingle to an existing beach ADVANTAGES - cheap and easy to maintain, widens beaches, greater protection from flooding and erosion DISADVANTAGES - expensive, has to be constantly maintained

Question 36

what is dune regeneration and what are its advantages and disadvantages?

Answer 36

•creating or restoring sand dunes, where marram grass can be planted to help dunes develop ADVANTAGES - cheap, prevents flooding and erosion, natural DISADVANTAGES - time consuming, protection is limited in certain areas

Question 37

what is dune fencing and what are its advantages and disadvantages?

Answer 37

•fences constructed on a sandy beach along the seaward face ADVANTAGES - minimal impact of natural systems DISADVANTAGES - unsightly, regular maintenance needed

Question 38

what is managed retreat?

Answer 38

•allowing sea to flood and/or erode areas of low value land •cheap, easy and doesn’t need maintaining •creates new habitats for plants and animals •protects areas in the long run from flooding

Question 39

what is happening to the holderness coast?

Answer 39

•is it retreating due to erosion •prevailing winds moves material south along the coast by longshore drift •1.8m of land is lost every year to the sea

Question 40

how is the city of Mappleton (Holderness Coast) protected?

Answer 40

•rock armour to absorb wave energy •rock groynes to build a beach up

Question 41

what conflicts did the defences of the Holderness Coast cause?

Answer 41

•loss of land •coastguard and lifeboats are at risk of erosion •loss of habitats •gas terminal is protected by rock armour - costing £6.6 million •maintaining the defences is becoming expensive

Question 42

what are social, economic and environmental impacts that coastal erosion has had on the Holderness Coast?

Answer 42

S - 30 villages lost since Roman times, visitor numbers are decreasing, gas terminal is at risk (provides 25% of Britains gas supply) Ec - £2 million was spent in 1991 for protection, property prices have fallen, visitor numbers are decreasing, lost around 10 caravan pitches a year En - cliffs made from till are easily eroded, gas terminal is at risk