Coasts GW 3 - done Flashcards
With the use of examples, explain how limiting damaging activities help in managing coastal areas.
laws and regulations
D:
Damaging activities are those that interrupt the functioning of natural systems, such as blasting coral reefs, clearing of mangroves and dumping waste into coastal areas. Banning these activities are costly and inefficient, so authorities try to limit the activities instead.
EX:
- Sand dunes at Port Philip in Australia are stabilised by plants, but were trampled upon by tourists visiting the beach.
- Sand dunes were prone to wind erosion, and sand partly buried the houses behind them.
- To allow the dunes to recover, authorities fenced off the dunes and built access paths to the beach.
S: This allows the plants on the dunes to recover and stabilise the dunes again.
L: However, the fences are ugly and does not provide access to the entire beach, which may reduce tourist flow.
With the use of examples, explain how protecting coastal resources helps in managing coastal areas.
laws and regulations
D:
Strategy to prevent resources from being exploited or depleted. Examples are fish populations which are vulnerable due to overfishing; and coral reefs which are vulnerable as destructive fishing methods are used.
EX:
- In Goat Island Marine Reserve in NZ, zones have been marked off to prevent commercial fishing
- Protects ecosystems, allowing endangered fish and species time and space to breed and thrive
S: The Goat Island Marine Reserve in NZ is now a tourist attraction thanks to its plentiful fish, with 14 times more snappers inside than outside it.
L: Strongly opposed by local fishermen, who have been fishing there for a long time. Access to a valuable resource & possibly major source of food denied.
With the use of examples, explain how restricting development in areas prone to natural hazards helps in managing coastal areas.
laws and regulations
D:
Natural hazards such as tsunamis can cause devastating damage to natural environments and human activities. National governments and local authorities develop management policies to deal with the threat of natural hazards. Research is done on the hazard’s severity and frequency, and the results are used to create laws.
EX:
- USA, the Federal Emergency Management Agency (FEMA) steers development away from areas prone to flooding or coastal erosion.
- Indonesian laws restrict new farms and residences from being built on low-lying coastal areas.
S: Avoid paying for reconstruction of destroyed infrastructures. Have more budget for more important issues, reduced loss of lives.
L: People may be resistant to moving due to various reasons (living there for a long time, paid a lot of money, nice view). It costs money to move people and get them to move. Less docks and ports.
With the use of examples, explain how beach nourishment helps in managing coastal areas.
soft engineering
D:
Slows down erosion of beaches. It uses sand from an external source or dredged up from the seafloor to replenish the sand on a depleted beach.
EX:
Sentosa, SG, where beach material of fine sand was brought in to replenish Siloso, Palawan and Tanjong beaches.
S: The beach becomes aesthetically pleasing and draws in tourists.
L: It can be costly and the beach can continue to erode, meaning more sand has to be brought in eventually. Sand can erode and suffocate corals offshore.
With the use of examples, explain how planting vegetation and stabilising dunes helps in managing coastal areas.
soft engineering
D:
Sand dunes can be stabilised by planting grasses. Roots will anchor the sand and prevent erosion by wind/waves. Over time, the grasses become established and the dunes will become more stable.
EX:
Triton Place in Western Australia has vegetated sand dunes & an access fence to prevent the dunes from being disturbed by human traffic. Matting is also placed on the dunes to hold them in place while the grasses grow. The matting then slowly rots away, providing nutrients.
S: Helps to stabilise the coastline and reduce coastal erosion by waves or winds.
L: Maintenance of fences, paths and monitoring of the dunes can be expensive. Fences may even have to be replaced when sand gets too tall.
With the use of examples, explain how encouraging coral reef growth helps in managing coastal areas.
soft engineering
D:
Coral reefs help reduce wave energy and serve as a breeding ground for fish.
- Artificial reefs can be created by placing lasting materials such as steel or concrete onto the seafloor.
- Corals, other marine creatures and vegetation, colonise the materials and start to function as a natural reef
EX:
- Since 1996, the Maldives has been operating a coral-growing programme
- Structures of welded construction steel rods placed off the coast of Ihuru
- Charged with low voltage solar-generated electricity to speed up coral growth
S: Corals grow 3-5 times faster, and the island now has a wide variety of corals, marine animals and organisms.
L: Expensive and takes decades before results begin showing. The places also have to be monitored.
With the use of examples, explain how building seawalls help in managing coastal areas.
hard engineering
D:
Constructed to protect coastlines against wave attacks by absorbing wave energy. Made of concrete or stone and built parallel to the coast.
EX:
Over 70% of Singapore’s coastline is covered by seawalls and rock slopes to help against coastal erosion.
S: Prevents erosion to coastal area, and protects area against wave action by reflecting waves.
L: Expensive to build & maintain as they face risk of collapsing. Erosion at the base of the seawall may cause it to collapse after a long time.
With the use of examples, explain how gabions help in managing coastal areas.
hard engineering
D:
Wire cages filled with crushed rocks, built along a shore or behind a beach. There are gaps between the rocks and the cages, allowing water to pass through them.
EX:
Andaman Coast, Thailand. ECP, Singapore.
S: They are effective against high energy waves as they can weaken wave energy when water passes through the gaps in the rocks and wires.
L: However, they are expensive as they have to be maintained as they get easily corroded by seawater. They are also prone to vadalism and excessive trampling.
With the use of examples, explain how building breakwaters help in managing coastal areas.
hard engineering
D:
Helps break the force of the oncoming waves. Can be built either parallel to the coast or with 1 side attached to the coast. When built offshore, there is a zone of calm water behind them where a lot of deposition occurs.
EX:
Almeria, Spain. ECP, Singapore.
S: Materials can deposit and build up in the calm zone of water behind the breakwaters, and the calm zone can be used as a harbour for boats.
L: They are ugly and provide uneven coastal protection. Areas further away from the breakwaters face erosion, wave action and flooding.
With the use of examples, explain how building groynes help in managing coastal areas.
hard engineering
D:
Low walls constructed at right angles to the shore. They absorb and reduce wave energy and causes materials to be deposited on the side of the groyne facing longshore drift.
EX:
Along the coast of Eastbourne, UK. ECP, Singapore.
S: Retains sediments that might otherwise be removed due to longshore drift. Helps reduce overall coastal erosion.
L: The downdrift side of the groyne is not protected and faces worse erosion, leading to uneven coastal protection.
With the use of examples, explain how tetrapods help in managing coastal areas.
hard engineering
D:
4-pronged concrete structures that help dissipate wave energy. Stacked offshore in an interlocking position. Allows water to pass around them instead of hit against them so no powerful backwash is generated.
EX:
Hokkaido, Japan. Crescent City, California.
S: Tetrapods can be placed quickly compared to other structures as they are precasted. Crescent City has used them to protect against tsunamis which occured many times.
L: However, they are ugly and are expensive to build. They are also dangerous to swimmers, surfers and boaters.
