Coasts GW3 - How to manage coasts pg 56 - 72 Flashcards
coast GW3
How does climate change cause the coastline to slowly disappear? How does it then affect property owners?
Sea level rise causes coast to disappear in a few years. Climate change brings high tides and erosion of coastlines during storms. Storms destroy houses which may cause them to eventually topple into the ocean, along the beach
coast GW3
What is the problem with building rockwalls to protect housing along the beach?
Rockwalls only causes more erosion, do nothing to help the beach. It creates a boulder coastline which is unsightly
coast GW3
How is the government trying to slow down the pace of erosion? How effective is it?
Dumping of sand to slow pace of erosion. However it is a temporary and expensive solution
Planned retreat – keep moving back when coastline moves back
Coastal erosion eg Australia beach
coast GW3
2 main approaches to manage coastal areas
- (3)
- (2)
- Laws and regulations (rules and regulations: protect sth or sb)
Limit damaging activities
Protect coastal resources
Restrict development in areas prone to natural hazards - Coastal protection measures
Soft and hard engineering
coasts GW3
Laws and regualtions
1. ?
- Limit damaging activities
E: - Banning vs limiting activities – Blast fishing, clearing mangroves for fish farming, dumping waste into ocean
- Constructing man-made facilities (docks, marinas) to replace natural areas
E: In Port Phillip, Melbourne, authorities fenced off the dunes and built access paths to the beach
(+) allow dunes to recover, do not allow people to trample on the dune
(-) less attractive, do not allow visitors and residents access to all parts of beach
coasts GW3
Laws and regualtions
2. ?
- Protect of coastal resources
E: - Preventing resources from being overexploited or overused
Eg: In Goat Island Marine Reserve in New Zealand, marine reserves has been set up to protect the fishes in areas where overfishing occurs
(+)protect marine ecosystems and allow fish to breed and thrive
(-) potential long-term benefits of marine reserves may be insignificant and marine reserves are a clash of interest with local fisherman
coasts GW3
Laws and regualtions
3. ?
- Restrict development in areas prone to natural hazards
E:
- Natural hazards, disastrous to natural environments and human activities.
- despite occurrence and unpredictability, people still
attracted
- coast provide natural resources like food and building materials
- residents and investors, spend more in construction and maintenance, prepare for emergencies
E: In Indonesia, laws restrict new farms and residences from being established on low-lying coastal areas.
‘Planned retreat policy’
Make policy to help people plan when surveying land
(+)
what is soft engineering?
examples (3)
Protection against erosive waves using natural processes
[uses natural material that blends in with environment]
- Beach nourishment
- Planting vegetation and stabilising dunes
- Encouraging coral growth
what is hard engineering?
Construction of physical structures to protect coasts against the erosive power of waves
[hard structures]
- Gabions
- Breakwaters
- Seawall
- Tetrapods
- Groynes
difference between soft and hard engineering
material used
coasts GW3
Soft engineering
1. ?
- Beach nourishment
E:
- from external source to replenish sand on depleted beach
- come from another beach or be dredged from the sea floor
E: In Sentosa, Singapore, beach material of fine sand was brought in to replenish Siloso, Palawan and Tanjong beaches
(+) offers protection to the immediate inland area, aesthetically pleasing
(-) costly and time-consuming
coasts GW3
Soft engineering
2. ?
- Planting vegetation and stabilising dunes
Plant vegetation:
E: - mangrove
Eg: Mangrove restoration in Thailand after Aceh-Andaman Tsunami that damage of coastline in 2004.
protect against cyclones, coastal erosion, and any future killer waves.
(+) stabilise coastline, absorb wave energy
(-) not immediate protection,
stabilising dunes
E:
- planting grasses
- matting put over dunes, grass planted through matting
- over time, established and dune more stable
Eg: In Australia, vegetation planted on sand dunes to hold sand, fence to prevent from being disturbed by human traffic –> stablise dunes
(+) matting add nutrients to sand
(-) not immediate effect, fence need be constantly replaced
coasts GW3
Soft engineering
3. ?
- Encouraging coral reef growth
E:
- measures can be taken
- serve as breeding ground and nursery for fish
- artificial reef: lasting material (steel / concrete) on sea floor
- corals with vegetation and marine creatures, colonies material –> natural reef
Eg: the Maldives, operating a coral-growth programme, curb severe beach erosion on islands, 3 to 5 times faster than normal
coasts GW3
Hard engineering
1. ?
- Seawalls
E:
- made of concrete or stone, built parallel to the coastline
- absorb wave energy
Eg: The Netherlands built seawalls on their coastline, low-lying, prone to flood, reduce 20% of flood
(+) absorb wave energy
(-) unsightly, costly
coasts GW3
Hard engineering
2. ?
- Gabions
E:
- Wired cages filled with rocks which weaken wave energy when the gabions are placed in front of the coastline
- gaps alow water to filter through
Eg: In Thailand, gabions along the Andaman Coast successfully protect the coast from erosion
(+) absorb wave energy, reduce coastal erosion, weaken wave energy
(-) unsightly, costly
