Q1. Examine the success of coastal protection measures in Singapore. Singapore, as a small island nation, has been experiencing continued coastal erosion for the longest time ever. As such, some coastal protection measures have been undertaken to ensure that land-scarce Singapore does not lose anymore of its precious land, which it needs to combat the burgeoning population as well as for various industries for economical growth, not to mention for recreational activities that Singaporeans caught up in the rat race desperately need. In my essay today, I shall be examining the success of coastal protection measures in Singapore.
Let us now look at different areas of Singapore where coastal protection measures have been implemented and to what degree of success. Firstly, on the island of Pulau Tekong, the largest of Singapore’s outlying islands and used exclusively for army training, more than 1,000 mangrove trees on its north-eastern coastline are at risk of falling due to coastal erosion. Deputy director of National Parks’ National Biodiversity Centre, Dr Lena Chan, has said that the erosion, with mud being scraped out, is due to movements of ships and strong waves in the area.
The erosion has affected 3km of north-eastern shore, posing a threat to the 92 hectares of mangroves in Pulau Tekong which is one of the largest remaining mangrove areas in Singapore with a mature and undisturbed habitat. At some points, the extent of the erosion was as deep as 1. 2 metres below the level of the mangrove berm. The first stage in the restoration process will be to fill the eroded parts below the mangrove berm with mud-filled biodegradable sacks. Next, loosely-placed stones will be placed in front of the berm as a shoreline stablisation measure.
Around 8,000 mangrove saplings will be planted in front of the stones to help deflect the waves. The saplings will also serve to increase the biodiversity of the mangroves population on Pulau Tekong. As a further anti-erosion measure, two rows of bakau (a type of mangrove tree) poles will be set up in front of the saplings to be the “front battle line” to further reduce the effect of the waves, said Dr Chan. However, it is felt that this coastal protection measure implemented is not very successful as it is not sustainable and may even have an adverse impact on the environment.
The mud can be continuously eroded and transported away could have serious consequences on wildlife living within coastal environment. For instance, the coral reefs at Waikiki Beach of Hawaii were destroyed as imported sand got washed out to sea and covered the corals. This is very important as the reefs of islands used by the Singapore military in live-firing exercises are among some of the healthier ones in the country, and Pulau Tekong is among such islands. The corals would be thus deprived of sunlight which they need to survive.
One such testament to the danger the coral reefs at Pulau Tekong would be that of Singapore itself, where land reclamation led to muddy and polluted water and killed surrounding coral reefs. Also, the beach nourishment conducted by filling the eroded parts with mud-filled biodegradable sacks can be very expensive and impractical, as the National Parks Board has to constantly transport large quantities of mud to fill up beach. Then again, the mangroves would serve as a deterrent to coastal erosion, as they have long and curved roots that prop up from soil, trapping sediments and extending the coastal land seawards.
However, as sediments build up along coast after planting mangroves, depth of coast may become shallower and thus affect marine activites. This is rather relevant to Pulau Tekong as being a military training ground, military vessels are expected to enter and leave its territory, but they may be hindered by the shallow coast. Secondly, the reclaimed coastline of Marine Parade is protected by a series of short seawalls, each averaging 30 meters in length. As Singapore is a growing nation that faces a shortage of land, the only viable option is to continue to reclaim land.
To prevent such land from being eroded away through wave dynamics, Singapore has chosen to use sea walls here, which is a rather successful coastal protection measure. Seawalls are especially useful in protecting reclaimed land as they absorb the energy of waves before they can erode away loose materials. However, they can only absorb the energy of oncoming waves, but are unable to prevent the powerful backwash of refracted waves from washing away beach materials at the base and underneath the walls.
Also, the sea walls will be continuously undermined over time and will eventually collapse. As such, repairs have to be done frequently but such repairs are often expensive. Seawalls are costly to build and maintain as constant repairs have to be made to prevent their collapse. Then again, we do not have a choice in land-scarce Singapore as we must make use of every opportunity to obtain more land for economic as well as social growth. With more land, it can be utilized for economic purposes as well as recreational purposes.
Although Singapore is land-scarce, it certainly does not suffer from a lack of government funds, and thus such an effort has to be put towards maintaining seawalls simply because we do not have a choice as a nation, though rich, facing land shortage, and thus sea walls are largely successful in Singapore. Thirdly, there have been breakwaters constructed along East Coast Park. The shoreline along what we know as the East Coast Park is different from those at either Labrador Park or the north shore, in the sense that obviously, its recreation potential is much higher.
This is because of the quality of the sand present there, by natural means or otherwise. Not surprisingly, therefore, given the recreational value of this beach, efforts have been made by the government to protect it from erosion. This is despite the fact that the fetch here is shorter than that at Labrador Park. Erosion of greater severity occurs in this area as during November to January, Singapore and Peninsular Malaysia are affected by the north-east monsoon.
This is by far the wettest time of the year because the strong monsoon winds pick up moisture from the South China Sea before arriving at Singapore and the east coast of Peninsular Malaysia. Although Johor bears the brunt of the storm waves brought by the north-east monsoon, the waves at the southernmost end of Johor are refracted round the southern tip, such that they are no longer approaching land from the north-east, from which Singapore would be quite adequately sheltered by Johor.
Instead, they are approaching land from the south-east, from which Singapore receives little or no protection. During the north-east monsoon, the waves along the East Coast Park approach at an oblique angle to the shore. When these waves break, the water rushes up the shore diagonally, carrying the sand on the beach along with it in the same direction. However, once the water starts to recede back to the sea, it will respond to gravity and drag the sand straight down the beach perpendicular to the shore.
The water from the next breaker will transport the sand up the beach diagonally again and the cycle continues. The net result of this is that sand is moved along a beach as a result of what is termed longshore drift. This explains why the beach at the East Coast Park must be protected. Protection is carried out at the park by the construction of several breakwaters built parallel to the shore. When sea waves impact on these structures, their energy is dissipated as breakwaters protect coast and harbor by reducing force of high energy waves before they reach the shore.
However, East Coast Park will not receive any new supply and thus be eroded away, albeit only over a very protracted period of time, as the breakwaters will still prevent sea waves from inflicting much erosion upon the coast. Thus, the breakwaters are largely successful as they have served their purpose although money will have to be spent on constant repairs when they are weakened by the waves, but Singapore does have funds to expend on such purposes which will better our circumstances as a nation facing land shortage.
In addition, gabions, wire cages usually filled with crushed rocks, and then piled up along the shore to prevent or reduce coastal erosion by weakening wave energy, have also been constructed along East Coast Park to hinder further erosion, but I find that they are largely unsuccessful as they are only short term solutions, lasting but five to ten years at most.
On top of that, the wire cages would need constant maintenance as they are easily corroded by seawater, and the rust formed could negatively impact marine life in the surroundings, and the gabions can also be affected by excessive trampling and vandalism. Furthermore, composing of metal wires they can become potential dangers on the beach should they be transported to the beach after breaking apart, and they are also unsightly, which would destroy the beauty that one would typically enjoy at a recreational location such as East Coast Park.
These are the common coastal protection measures undertaken to protect Singapore’s precious coasts. I would say that they are largely successful, but only because in the context of Singapore, we are a country facing a land shortage crisis, and thus all must be done to preserve our land, even if it means constantly using government funds to pay for maintenance of such measures.
Elsewhere, such coastal protection measures may not be considered successful for they are not that sustainable, costing much to maintain and create, but in Singapore, it is our only option should we not want to lose valuable land area. In addition, we have the funds to continue supplying such measures, which makes the coastal protection measures to a large extent successful in Singapore.
