coastal management Flashcards

0
Q

what is erosion

A

removal of rock and sand particles as a result of wind and wave action

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1
Q

issues in coastal environments

A
  • development
  • rivers/lagoons
  • erosion
  • pollution
  • population growth
  • introduced plants
  • tourism
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2
Q

what are the four types of coastal erosion

A

hydraulic action
corrosion abrasion
corrosion solution
attrition

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3
Q

what is hydraulic action

A

when a wave hits a headland, the trapped air is compressed which weaken the cliff

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4
Q

what is corrosion- abrasion

A

bits if rock and sand in waves grind down cliff surfaces

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5
Q

what is corrosion (solution)

A

acids contained in sea water dissolve some rock types

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6
Q

what is attrition

A

waves smash rocks into smaller particles to use in abrasion

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7
Q

how are sea cliffs formed

A

large waves break and cut the foot of the cliff causing wave cut notches
these notches enlarge until the cliff collapses

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8
Q

how are headlands and bays formed?

A

the sea erodes a section of the coast

the soft rock erodes quicker causing bays to form and the hard rock is left forming headlands

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9
Q

how do caves, arches, stacks and blowholes form?

A

caves occur when waves force their way into cracks in a cliff
arches occur when the cave breaks through to the other side
stacks are formed when the arch becomes bigger and breaks at the top leaving a column
blowholes form when cracks in the rock create a gap right through to the top

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10
Q

what is a crest?

A

peak of the wave

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11
Q

what is a trough?

A

bottom of the wave

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12
Q

what is the fetch

A

distance wind travels over the ocean to form waves

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13
Q

what is the size of a wave influenced by:

A

wind strength

wind duration

wind speed

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13
Q

what is swash

A

when the water is washed up the beach

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14
Q

what is backwash

A

when the water runs back down the beach

15
Q

what is the difference between constructive and destructive waves

A

destructive waves make the beach steeper we they drag sand down the beach
constructive waves push sand up the beach

16
Q

which waves have strong backwash and weak swash

A

destructive waves

17
Q

which waves have weak backwash and strong swash

A

constructive waves

18
Q

what is longshore drift

A

where the swash carries the material up the beach at an angle and the backwash travels back in a straight line
this continually transports materials along the coast

occurs in a zig zag

19
Q

what is deposition

A

happens when the swash is stronger the the backwash

when waves lose energy and drops any particles it’s been carrying

20
Q

name 5 depositional features

A
beach
spits and bars
tombolo
storm bay/ sand bank
sand dunes
21
Q

what is coastal management

A

the controlled retreat of the coastline

22
Q

what is the difference between soft engineering and hard engineering

A

soft- less expensive and more sustainable

hard- expensive, unsustainable

23
Q

why do we need coastal management

A

to prevent beaches from eroding away and disappearing as this occurs naturally

24
Q

what are some effects of costal erosion

A
  • loss of land
  • loss of infrastructure
  • loss of property
  • economic loss- tourism
25
Q

name some hard engineering approaches

A
groynes
sea wall
rock bars
rock gabions
metal pilling 
rip rap
revetments
26
Q

name some soft engineering approaches

A

sand pumped
replanting grass
boardwalks
mangrove trees