Coasts KQ3 Flashcards

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1
Q

What is management?

A

Controlling development and change based on rules and regulations

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2
Q

What is sustainability?

A

Managing change in a way that does not does not compromise the environment for present and future generations

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3
Q

Laws and regulations in managing coasts

A

1) Limiting damaging activities
2) Protect coastal resources
3) Restrict development in areas prone to natural hazards

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4
Q

L&R: Limiting damaging activities

A
  • Damaging activities: Activities that disturb the functioning of the natural system
  • Banning activities is costly, ineffective and unsustainable in long run
  • Govts restrict activities by meeting demands of people while ensuring maintenance of coastal environment
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5
Q

L&R: Limiting damaging activities example

A

Port Phillips, Australia
- Sand dunes destabilised by visitors
- Authorities fence off dunes and construct access pathways into the beach

L: Fencing unattractive and restrict visitors from certain parts of the beach

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6
Q

L&R: Protect coastal resources

A
  • Prevents resources from being depleted/overused

i.e. Fish near coastlines overfished
- 90% of marine animals caught close to shore
- Blasting and cyanide fishing used, destroying coastal habitat
- Needs to be prevented to protect and preserve coast

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7
Q

L&R: Protecting coastal resources example

A

1) Wakatobi National Park, Indonesia
2) Goat Island Marine Reserve, New Zealand

  • Zones blocked off to prevent commercial fishing
  • Enable marine species to breed and thrive

L: Fishermen see access to resources and income as being denied

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8
Q

L&R: Restricting development in areas prone to natural hazards

A
  • Protects people and coastal resources
  • People attracted to coasts despite unpredictability of natural hazards

A:
- Coasts provide natural resources and food
- Coasts have substantial range of built services such as docks, ports, housing and recreational facilities

L:
- More expensive to construct and maintain coastal buildings
- Mental preparation needed in case of emergencies

  • Management policies needed to deal with threats and natural hazards in coastal areas (Govt/Authorities)
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9
Q

L&R: Restricting development in areas prone to natural hazards examples

A

1) Retreat/Relocate from areas prone to natural hazards
- Federal Emergency Management Agency (FEMA) diverts development away from areas vulnerable to floods/coastal erosion

2) Avoidance/Regulating development
- Govts restrict development of farms, buildings and infra. in vulnerable, low-lying coasts.

3) Defence via coastal protection measures
- Soft/Hard Engineering measures

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10
Q

Coastal Protection measures

A

> Soft Engineering methods
- Protecting coasts using natural processes
- Does not involve construction of physical structures

1) Beach nourishment
2) Planting vegetation
3) Stabilizing dunes
4) Encouraging coral reef growth

> Hard Engineering methods
- Building physical structures to shield coasts from erosion

1) Sea Walls
2) Gabions
3) Groynes
4) Breakwaters
5) Tetrapods

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11
Q

SE: Beach nourishment

A
  • Replenishing sand lost through erosion by adding fresh sand brought in from other beaches or dredged from seafloor

A: Transforms eroded coast into wide sandy beach that provides protection to nearest inland areas

L: Trucking, dredging and piping is costly and time consuming
- Sediments swept into sea may choke corals and dredging destroys seafloor habitats
- Not sustainable in long run, re-erosion occurs if no other measures are in place

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12
Q

SE: Beach nourishment examples

A
  • Palawan, Siloso, Tanjong beach, Sentosa
  • Beaches made more attractive after beach nourishment
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13
Q

SE: Planting vegetation (Mangroves)

A
  • Planting of trees and shrubs to stabilize shoreline

A: Wave energy absorbed and dissipated by dense networks of roots
- Buffer zones formed between seas and inland coastal areas
- Roots able to trap sediment and promote deposition, extending coasts/form small islands

L: Takes long time to stabilize sediments on beach
- Not effective enough to withstand natural hazards
- Threatened by human activities

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14
Q

SE: Stabilizing dunes

A
  • Planting grasses (Maran grasses) so roots can anchor to sand and prevent erosion
  • Matting placed over dunes and plants are planted over matting

A: Vegetation becomes rooted and stabilizes dunes
- Matting rots away, adding nutrients to the sand

L: Fences used need regular maintenance and need to be made taller when sand accumulates
- May restrict access to coasts

e.g. Port Philip

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15
Q

SE: Encouraging coral reef growth

A
  • Artificial reefs grown in open waters to weaken wave energy
  • Low voltage currents passed through cages, speeding up coral reef growth
  • Serves as breeding grounds and nursery for fish

A: Corals grow 3-5x faster

L: Sites must be suitable for coral reef growth
- Effects not immediate, corals still take long time to grow
- Research and equipment costly

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16
Q

SE: Encouraging coral reef growth example

A
  • Island of Ihuru, Maldives
  • Colonising efforts since 1996
  • Wide variety of corals and marine creatures
  • Received international recognition
17
Q

HE: Sea walls

A
  • Concrete or stone walls built parallel to coastline to absorb wave energy

A: Absorb wave energy and reflect approaching wave energy

L: Expensive to construct and maintain in order to prevent collapse
- Scouring common when wave energy reflected to base of sea walls, causing undercutting and collapse

18
Q

HE: Sea walls example

A
  • East-Coast park, 4800m
  • Drake islands, England
  • Collapsed due to scouring
19
Q

HE: Gabions

A
  • Wire cages filled with rocks and piled up against shore

A: Waves weaken when passed through rocks

L: Unsightly, expensive to maintain
- Easily eroded and damaged (vandalised)
- Water causes corrosion to cages (Hazardous to humans)

20
Q

HE: Gabions examples

A
  • East-Coast park
  • Gabions removed due to vandalism
  • Northfolk, UK
21
Q

HE: Breakwaters

A
  • Built parallel to coast off-shore and creates zone of sheltered water behind it
  • Converging waves towards BW, diverging waves behind BW

A: Encourages deposition behind it, forming beaches
- Sheltered areas used as harbour/marina

L: Unattractive and costly to construct
- Only protects coast behind it

22
Q

HE: Breakwater examples

A
  • East-Coast park
  • Portland Harbour, England
  • Resulted in erosion and flooding problems, affecting properties, beaches and communication infra.
23
Q

HE: Groynes

A
  • Low walls constructed perpendicularly to shore to retain sediments transported by LSD

A: Absorb and decrease wave effects on coast
- Allow materials to be deposited on updrift side of groynes facing LSD

L: Material erodes on downdrift side before being deposited on updrift side.
- Makes coast uneven and unattractive
- Areas not protected by groynes still eroded

24
Q

HE: Groyne examples

A
  • East-Coast park along abrupt turns of coast
  • Sandy Hook, New Jersey, USA
  • Groyne demolished due to continued erosion on downdrift side of groyne
25
Q

HE: Tetrapods

A
  • 4-pronged concrete structures stacked off shore/along shore in interlocking position to disseminate wave energy

A: Allow waves to pass through and around them instead of hitting and reflecting off them
- No backwash generated, decreasing chances of damage
- Precasted and easily deployed at vulnerable coasts

L: Unsightly and dangerous to people
- Casting and transportation is costly

26
Q

HE: Tetrapods examples

A
  • Hokkaido, Japan
  • Crescent city, North California
  • Prevent coastal erosion and decrease impact of tsunamis