Among Prime Minister Lee Hsien Loong’s suggestions for tackling rising sea levels during his 2019 National Day rally was one that involved reclaiming a series of islands off the coast of Marina East in Changi, to connect them to dams and create a reservoir, similar to Marina Reservoir.
Singapore has also already put in place some measures, including the use of polders, which are stretches of land below sea level and reclaimed through the construction of dykes, drainage canals and pumping stations.
There is an ongoing polder project on Pulau Tekong, led by the Housing and Development Board, which is more than half complete and expected to be completed by the end of 2024.
National Development Minister Desmond Lee said last month that the project, the first of its kind in Singapore, will help the country gain experience in polder development, which “could be an option for the protection coastline and resilience against sea level rise”.
There are also plans to build infrastructure higher above sea level. Professor Benjamin Horton, director of Earth Observatory Singapore at Nanyang Technological University, said Changi Airport , for example, built the terminal 5 to 5.5 m above current sea level to protect against future sea level rise.
“We can also think about technical advances that will allow buildings to float,” he added.
PUB’s Coastal Protection Service is also looking at other possible solutions, with Principal Deputy Manager Sarah Hiong reiterating that it is “important to study all options, even long-term ones, thoroughly”.
Here are some other alternatives that Singapore is investigating:
ROCK WALLS AND CLADDING
Both are hard structures that protect against coastal erosion. Currently, PUB says they line around 70% of Singapore’s coastline.
“Building seawalls around the whole of Singapore is a simple and straightforward solution but not entirely feasible, as we also need to consider the interactions between land and sea,” said lead engineer Eugene Lim of the Coastal Protection Team. of PUB.
For example, this could include natural coastal habitats, recreation and industries that require waterfront access.
“It will also not be aesthetic for the public. Try to imagine having a big wall built all over Singapore’s coastline,” he added.
NATURAL HYBRID SOLUTIONS
Mr. Lim said PUB intends to explore hybrid solutions, which combine engineering solutions with nature-based elements, including planting mangroves, seagrass or vegetation.
One of the benefits of this option, Lim said, is that it offers Singapore the opportunity to create habitats to enhance biodiversity.
However, it will not be possible to rely entirely on nature-based elements.
Using the example of mangroves, Associate Professor Koh Tieh Yong, a weather and climate specialist at the School of Science and Technology, Singapore University of Social Sciences (SUSS), said that when the level of sea rises, the higher sea water will always seep into the mangrove land.
“During a storm, the roots of the mangroves serve to break the waves and hold the soil, reducing coastal erosion. In this way, mangroves can protect areas further inland until the sea rises beyond a level where even mangroves cannot thrive.
Thus, it will always be necessary to combine it with man-made structures such as seawalls as the primary solution to sea level rise, he said.
Another disadvantage is that most of Singapore’s coastal land is needed for residences, industries, seaport, airport or recreational beaches and therefore cannot be replaced by mangroves.
MULTIFUNCTIONAL COASTAL DEFENSES
Due to the scarcity of land in Singapore, multifunctional structures such as Marina Barrage would be an ideal solution, Lim said.
The dam not only provides a source of water supply, it acts as a flood control and even a place of recreation – a “family hotspot” for picnicking, flying kites and spending time quality time together, he said.
An overseas example that protects against sea level rise, highlighted by Ms Hiong, is the Katwijk underground car park in the Netherlands, where much of the country is below sea level.
Designed by the Royal Institute of Netherlands Architects, it won the Dutch Building of the Year award in 2016.
Located next to a popular beach, the project is a parking lot that can not only house 650 cars, but also plays a vital role as a sea wall to protect the small eponymous town from future flooding.
What’s interesting about the project, said Ms. Hiong, is that “you can’t even say it’s actually a coastal protection measure” because it’s hidden in a sand dune. sand so that it merges with the waterfront.
“So that’s an example that really inspired us…to build something that not only has such significant utility to the nation, but also something that the public will actually appreciate,” she said.