Should Coastal Environments Matter? CHAPTER 1 COASTS Should Coastal Environments Matter?

CHAPTER 1 COASTS Should Coastal Environments Matter? In this Chapter, you will explore three key questions: How and why are coastal environments different and dynamic? Why are coastal areas valuable? How can we manage coastal areas in a sustainable manner?

CHECK-IN: Coastal erosion in Australia http://www.youtube.com/watch?v=abU02rmVsKA&feature=related Watch the video on coastal erosion in Australia and answer the following questions: How does climate change cause the coastline to slowly disappear? How does it then affect property owners? What is the problem with building rockwalls to protect housing along the beach? How is the government trying to slow down the pace of erosion? How effective is it? How does climate change cause the coastline to slowly disappear? How does it then affect property owners? Sea level rise causes the 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, especially those built along the beach. What is the problem with building rockwalls to protect housing along the beach? Rockwalls only cause more erosion and do nothing to help the beach. It also creates a boulder coastline which is unsightly. 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.

CHAPTER 1 COASTS Should Coastal Environments Matter? Gateway 3: How can we manage coastal areas in a sustainable manner? How can coastal areas be managed? What are the coastal protection measures? Case study: East Coast Park

a. How can coastal areas be managed? Sustainable management of the coastline involves: A series of strategies (hard and soft engineering) Sustainable development of the coastline to benefit present & future generations Three approaches: Limiting damaging activities Protection of coastal resources Restricting development of areas prone to natural hazards Tell students to note that the three approaches are general ways to sustainably manage coastal areas. The hard and soft engineering measures are strategies that can be applied alongside the three approaches.

Why do you think fences are built around the sand dunes? Suggested answer: To prevent people from trampling on the sand dunes or grass / to prevent development on the sand dunes.

a. How can coastal areas be managed? Limiting damaging activities Banning vs limiting activities such as: Blast fishing, clearing mangroves for fish farms, dumping waste into ocean Constructing man-made facilities to replace natural areas.

Limiting damaging activities a. How can coastal areas be managed? Limiting damaging activities Read the article about the Bunaken National Park (http://www.sulawesi-info.com/bunaken.php) and answer the following questions: Identify the stakeholders who have a part to play in protecting the marine life in this area. Think of some potential problems that the stakeholders might face with the development of the marine park Suggested answers: 1. The stakeholders are: local communities, government officials, dive resort operators, local nature groups, tourists and scientists 2. The locals may not cooperate with the government officials and continue to overfish in the area if not strictly monitored. There might be conflict of interest in protecting the national park versus ensuring the local fishermen can earn a steady income from fishing. Dive resort operators might cause damage to the coral reef if they do not educate the tourists about protection of the resources.

a. How can coastal areas be managed? Protection of coastal resources Preventing resources from being overexploited or overused. For example, setting up marine reserves to protect the fishes in areas where overfishing occurs. This is a clash of interest with local fisherman who depend on the fish stock for a living. Refer to TB for more details.

a. How can coastal areas be managed? Restricting development in areas prone to natural hazards Watch the following video again and explain the ‘planned retreat policy’ which the Australian government used on the beachfront property. http://www.youtube.com/watch?v=abU02rmVsKA&feature=related Answer: Planned retreat policy is a policy where owners of beachfront houses have to move their houses or demolish them at their own cost the moment the house comes within 20 metres of the coastal escarpment (slope where erosion occurs) Refer to TB for more examples of restricting development in areas prone to natural hazards.

CHAPTER 1 COASTS Should Coastal Environments Matter? Gateway 3: How can we manage coastal areas in a sustainable manner? How can coastal areas be managed? What are the coastal protection measures? Case study: East Coast Park

b. What are the coastal protection measures? Compare Photograph A and B in terms of how you think they protect the coastline from erosive waves. A B Photograph A shows gabions on the coastline. They weaken wave energy as waves approach the coastline. Gabions need to be arranged properly along the coastline. However, they are an additional structure on the beach and are unsightly. Photograph B shows beach nourishment. This measure is easily implemented and increases the amount of sand of the beach to reduce the amount of beach erosion. However, it is an expensive and time-consuming solution. Images: ©Colin Babb/Wikimedia Commons; © Mark Gadsby/Wikimedia Commons

b. What are the coastal protection measures? SOFT ENGINEERING HARD ENGINEERING Protection against erosive waves using natural processes Construction of physical structures to protect coasts against erosive waves a. Beach nourishment Seawalls b. Replanting coastal vegetation b. Gabions c. Encouraging coral reef growth c. Breakwaters d. Groynes e. Tetrapods

b. What are the coastal protection measures? What are the disadvantages of each strategy? Beach nourishment Fine sand brought onto Siloso, Palawan and Tanjong beaches in Sentosa, Singapore. Planting vegetation to stabilise sand dunes Vegetation planted on sand dunes in Western Australia to hold onto the sand. Mangrove restoration in Thailand after damage of the coastline in the Dec 26, 2004 Aceh-Andaman tsunami. Encouraging coral reef growth Maldives has been operating a coral-growing programme where coral growth is sped up using solar-generated electricity. Disadvantages of the soft engineering strategies: Beach nourishment: Buying sand is costly and piping sand is time-consuming. If too much sediments are washed out to sea, they will suffocate the coral reef. Beach nourishment is only a temporary measure to slow down erosion. Planting vegetation: Vegetation takes time to stabilise the sediments on the beach. This measure may not be effective enough to withstand storms and repeated human trampling. This strategy will be a success only if people understand the value of planting vegetation and keep to the regulations. Encouraging coral growth: Research and equipment is required and this may be costly. May not successfully lead to rapid coral growth as it takes 20-30 years before results are evident.

b. What are the coastal protection measures? What are the disadvantages of each strategy? Seawalls Walls built parallel to the coastline absorbs wave energy. Breakwaters Built parallel to coasts offshore and create a zone of sheltered water between the breakwater and the coastline. Materials are deposited within the sheltered area to form beaches. Gabions Wired cages filled with rocks which weaken wave energy when the gabions are placed in front of the coastline. Disadvantages of the hard engineering strategies: Seawalls: Unsightly and costly to build and maintain. Initial success is common but not long-term success as backwash erodes base of seawall. Breakwaters: Unsightly and costly to build. Not the entire coastline will be protected if breakwaters are built only in a particular area. Gabions: Unsightly and costly to build and maintain. They are easily corroded by seawater and damaged by excessive trampling or vandalism.

b. What are the coastal protection measures? What are the disadvantages of each strategy? Tetrapods Concrete structures stacked in an interlocking position, allowing water to pass through them, reducing strong backwash and dissipating wave energy. Groynes Low walls constructed at right angles to the shore to retain sediments which are transported by longshore drift. Disadvantages of the hard engineering strategies: Tetrapods: visually unsightly for visitors and dangerous to swimmers, surfers if they hit against the structures. It takes time to build. Groynes: visually unsightly and causes downdrift erosion on one side of the groyne. Areas not protected by groynes are still eroded. Not necessarily constructed along the entire coastline. Images: ©Dr Wong; ©Roger Kidd/Wikimedia Commons

CHAPTER 1 COASTS Should Coastal Environments Matter? Gateway 3: How can we manage coastal areas in a sustainable manner? How can coastal areas be managed? What are the coastal protection measures? Case study: East Coast Park

c. Case study: East Coast Park Image: ©Sengkang/Wikimedia Commons

c. Case study: East Coast Park Uses of East Coast Park: The Park was reclaimed to alleviate problem of land shortage in the 1970s Recreational activities such as swimming, fishing, cycling, jogging, kite-flying Used for sports events. Sporting facilities developed in the same area View TB for more details Image: ©Sengkang/Wikimedia Commons

Value of protecting coastal environment c. Case study: East Coast Park Value of protecting coastal environment East Coast Park’s coastline is near residential area (100m from coastline) Population is vulnerable to changes in coastal environment in the long run Image: ©Sengkang/Wikimedia Commons

c. Case study: East Coast Park Measures adopted to protect the coastline On reclaimed land Hard engineering strategies (seawalls & breakwaters) were put in place to protect the coastline from coastal erosion 4,500m seawall with a strip of pebbles, sand, clay and silt in front of it Two types of breakwaters used to protect the coast and create beaches: gabion and riprap breakwaters Large drains acting as groynes built on the foreshore What are the problems that arose from the application of hard engineering strategies on the East Coast Park coastline? Refer to TB for more details. The problems are: Severe erosion at the base of the seawall making it unstable and ineffective High maintenance cost for the seawalls, therefore not a practical measure Vandalisation of gabion breakwaters

c. Case study: East Coast Park Factors undermining the success of the coastal protection measures Sediments from the Johore shoal reduced due to reclamation of land at Changi for Changi airport construction Sinking of reclaimed land of East Coast Park due to lack of beach material; more vulnerable to erosion Extreme high tide events worsened erosion; sand from beaches washed landward Responses Beach nourishment, breakwater reconstruction Constant maintenance

CHAPTER 1 COASTS Should Coastal Environments Matter? In this Chapter, you will explore three key questions: How and why are coastal environments different and dynamic? Why are coastal areas valuable? How can we manage coastal areas in a sustainable manner?