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| Serapong Reef at Jul 2025 |
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| Serapong Reef in May 2024 |
Mr Nasry hopes that the western coastal barrier will be built farther away from the nature spaces of Berlayer and Bukit Chermin. Alternatively, to set aside some land for the mangroves to retreat and colonise inland.
Full news article below the fold.
More about our surveys of Serapong reef.
You can see for yourself the mangroves at Berlayar Creek. More details in Mangroves just a few steps from Labrador MRT station.
You can also visit Changi shores for yourself. More details in "Changi - an easy intertidal adventure for the family".
Berlayer Creek mangroves and Sentosa’s Tanjong Rimau among nature spots at risk from coastal measures
Shabana Begum Straits Times Published Sep 07, 2025, 05:00 PM
SINGAPORE - As the Republic takes steps to armour its south-east coastline against rising seas with coastal barriers and tidal gates, the impact of their future construction on fragile habitats is causing some concern.
Nature groups conveyed their feedback to PUB before the national water agency released its coastal protection plans for the Greater Southern Waterfront and Changi in end-August.
These concerns will be taken into account in environmental impact studies to be carried out over the next couple of years before construction begins in the 2030s.
The protection measures will include bridge-like coastal barriers, a first for Singapore, to protect the Greater Southern Waterfront precinct – including HarbourFront and future homes on the Keppel Club site – from storm surges.
Nature experts have identified some habitats that are likely to be affected by construction and changes to water flow. They include Serapong Reef and Tanjong Rimau on Sentosa, and the mangroves of Berlayer Creek in Labrador and Changi Creek.
Three coastal barriers are expected to connect the western and eastern ends of Sentosa to the mainland. Each comprises a series of gates across the water channels that will remain open to allow vessels to pass except in extreme weather.
Two of the coastal barriers are expected to link mainland Singapore, around Tanjong Pagar Terminal, to Pulau Brani, and from Brani to the north-west coast of Sentosa.
Their design will be further refined in the next couple of years.
Mr Muhammad Nasry Abdul Nasir, executive director of the Singapore Youth Voices for Biodiversity, is concerned that the barrier across Brani and Sentosa would cut through Serapong Reef, which runs along the north-west coast of the resort island.
Sediment washed into the sea or from construction works could settle on the corals, potentially smothering parts of the reef. With water flow confined through the barrier’s gates, water movement across the channel may change, he noted.
“Corals like stronger currents because it keeps them clean,” said Mr Nasry, adding that Serapong is also home to many soft corals and a large number of red feather stars.
The flamboyant cousin of sea stars, the red feather star has brittle arms that resemble bird feathers.
“Seeing one feather star at a shore is already very impressive. I saw at least 25 of them during a survey at Serapong two months ago,” Mr Nasry recalled.
On the western side of Sentosa, the third coastal barrier will anchor on a spot on the mainland that will be determined following environmental impact studies.
Building the barrier at the narrowest parts of the channel may be most straightforward, but could risk impacting two key nature spots – Tanjong Rimau on the western coast of Sentosa, and Labrador Nature Reserve’s Berlayer Creek.
Tanjong Rimau hosts one of Singapore’s last remaining coastal cliffs and a rocky shore. Its geology features the sedimentary or layered rock formation of the Southern Islands.
Its rocks are about 220 million years old, formed from the overlapping layers of coarse and fine sand and silts from an ancient river environment. Across the Southern Islands, Tanjong Rimau’s rocky outcrop is the largest and most accessible of its kind, said Dr Stephen Chua from the NTU Earth Observatory of Singapore.
“It would be great to have the (coastal) barrier away from this outcrop, which is already exposed to erosion and likely to be affected by nearby construction. Sentosa and our Southern Islands have good geological value and have the potential to be a Unesco-worthy geopark collectively,” said Dr Chua.
Berlayer Creek is home to one of two remaining mangrove patches in the south of Singapore.
Mr Nasry hopes that the western coastal barrier will be built farther away from the nature spaces of Berlayer and Bukit Chermin, and towards the more urban Keppel areas. But this means the mangroves may be exposed to rising seas and storm surges, flooding the forests for longer.
Alternatively, if some land is set aside for them to retreat and colonise inland, the mangroves can continue surviving. Mangroves can serve as a living defence against rising sea levels as their roots trap sediment from the tides, allowing them to keep pace with rising seas.
Assistant Professor Gary Lei from the NUS Department of Civil and Environmental Engineering added that the coastal barriers should be built using precast components where possible to reduce construction disruptions at sea.
The amount of suspended sediments and oxygen should also be tracked, with construction paused during coral spawning season.
Changi
Over in Changi, some coastal protection measures involve building several tidal gates along the far eastern coastline. Tidal gates built at canal outlets will be closed during high tide and extreme coastal weather to keep seawater out.
With higher sea levels, the tidal gate may need to be closed more frequently, said Mr Lester Tan, chairman of the Marine Conservation Group at Nature Society Singapore. This would cut off the natural ebb and flow of waves that bring nutrients and sediment to the mangroves, as well as transport seedlings, affecting the forest’s long-term health, he added.
Prof Lei suggested building a tidal gate with multiple panels across the channel. While the gate is closed, the bottom panels could hover just above the sea bed so that some water can move in and out of the creek. This can also prevent silt from building up.
Ms Hazel Khoo, director of PUB’s coastal protection department, told The Straits Times that in its next phase of studies, PUB will work with relevant agencies, including the National Parks Board, to better understand and address any potential impacts on biodiversity.
“We will also engage stakeholders, including nature groups, and conduct environmental impact assessments to assess the potential impacts and develop appropriate mitigating measures before construction commences,” she added.
Nature Society’s Mr Tan said that as Singapore fortifies its shores in the next few decades, its entire coastline will be busy with construction work, including reclamation.
“The developments can be heavy-impact, impacting all shorelines at the same time. There will be no time for (habitat) recovery... Unfortunately, it is quite devastating for the blue spaces.
“It really depends on how we can phase the different developments for marine life to find a temporary new home each time.”
Coastal barriers to debut in S’pore: How do they shield shores from extreme sea levels?
Shabana Begum Straits Times Published Sep 14, 2025, 10:00 AM
SINGAPORE – From the 2030s, three novel structures that will protect Singapore from rising sea levels will start to take shape on the nation’s southern coast.
Called coastal barriers, these arm-like gates can open and close depending on weather conditions. It is the first time that such a coastal protection solution – a Dutch innovation – will be implemented in the Republic, national water agency PUB announced in end-August.
In response to The Straits Times’ queries on how such a barrier would be operated, Professor Bas Jonkman from Delft University of Technology in the Netherlands cited the example of the Maeslant Barrier in Rotterdam, pointing to how the public is alerted to the barrier closure at least 12 hours ahead of time.
“The warning needs to give sufficient time for vessels to move, and advanced forecast models are in use for this,” he said.
He added that many vessels move out of the Rotterdam port ahead of an incoming storm as it is safer in the ocean.
At the port, there is a higher risk of collisions with waterfront structures and other ships.
The closure of the gates themselves could take about two hours, and they remain closed “for several hours to stop the peak of the storm surge”, said Prof Jonkman, who is also a member of PUB’s Coastal Protection Expert Panel.
Coastal barriers are aimed at protecting an area from storm surges – higher-than-usual tides caused by storms brewing offshore.
By 2100, average sea levels around Singapore could rise by up to 1.15m. Storm surges can add another increase of 3m or 4m and cause coastal flooding if the shores are not protected.
In Singapore, a storm surge event could last three to five days. When such events are predicted here, the planned barriers will close for a few days.
The Republic intends to build two barriers linking mainland Singapore to Pulau Brani, and Brani to the north-west coast of Sentosa. The third barrier is expected to link western Sentosa to the mainland.
ST had earlier reported that government agencies here will further study the possibility of having the barriers serve as a “causeway” for visitors to reach Brani and Sentosa from the mainland.
Prof Jonkman told ST that such multi-use barriers are feasible, and some have already been rolled out in the Netherlands.
For example, the Eastern Scheldt Barrier in the Dutch province of Zeeland functions as both a bridge and a coastal barrier, he said.
There is also potential for the barriers to be an educational site on coastal protection for students and visitors, much like Marina Barrage is for water resources, he added.
While PUB has announced plans for the three coastal barriers in the Greater Southern Waterfront area in Singapore’s south, such infrastructure could potentially be deployed in other parts of the country’s shoreline.
The agency has since 2023 been studying the feasibility of installing coastal barriers near the south-western coastline – including Jurong Island, Pasir Panjang Terminal and the Tuas shipyards.
Prof Jonkman said: “This will require a comparison between a shoreline protection strategy and a barrier strategy, based on costs and impacts on the port and other functions. If there is heavy shipping, we need to find gate types that do not restrict it.”
He added that coastal barriers could also be part of Singapore’s future Long Island reclamation project that will protect the East Coast area.
Long Island is envisioned as three tracts of land reclaimed to higher levels off East Coast.
The initial barrier designs to protect the Greater Southern Waterfront were from infrastructure consultancy CPG Consultants, which worked with global engineering consultancy Haskoning on the study looking into coastal protection solutions for Singapore’s south-eastern coastline.
Haskoning’s flood risk expert Matthijs Bos, who is also from the Netherlands, said he had done analyses which found that extreme storm surge events that raise sea levels by 3m above Singapore’s average sea levels are likely to happen once every decade.
Given this, Mr Bos said he expects Singapore’s coastal barriers to close once every 10 years.
In the Netherlands, the Maeslant Barrier has closed only about three times since it was built in 1997, said Prof Jonkman.
It last closed in December 2023 before Storm Pia hit the Netherlands. The gates are programmed to close automatically when water levels are expected to rise by 3m, based on weather forecasts.
But with climate change resulting in more extreme weather events and higher mean sea levels, coastal barriers could be deployed more frequently.
Prof Jonkman said he expects that the Maeslant gates could close about once a year during extreme weather.
He added that compared with building a closed permanent dam as a coastal protection measure, coastal barriers can help keep a waterway open for shipping and environmental flows.
In the next couple of years, Singapore will further study the design of its coastal barriers, which will involve looking at construction methods and doing environmental impact assessments.
Prof Jonkman said coastal barriers could have an effect on the environment and ecology, and this needs to be looked into.
The Eastern Scheldt Barrier, which was built about 40 years ago, led to the loss of wetlands and intertidal areas.
“Nowadays, barrier designs are more open, having less construction in the waterway, leading to less environmental impacts,” Prof Jonkman said.
Nature groups told ST previously that the coastal barriers may impact a reef and Tanjong Rimau on Sentosa, and the mangroves of Berlayer Creek in Labrador.
