Singapore Plans Coastal Barriers, Tidal Gates and Long Island to Protect Its South-Eastern Shore

A Coastal Defence Line From Pasir Panjang to Changi

Singapore is preparing a continuous line of coastal defences from Pasir Panjang Ferry Terminal to Changi, following a four-year, S$18 million study of its City-East Coast region. The proposals include three coastal barriers linking Sentosa Island, Pulau Brani and the mainland, tidal gates at canal outlets, higher shorelines and new embankments. Construction is targeted to begin in the 2030s.

PUB, Singapore's national water agency, presented the measures at the country's first coastal protection exhibition. They form part of a programme expected to stretch across decades, combining engineering, environmental assessments and public consultation to protect the densely developed south-eastern coast.

About 30 percent of Singapore's land lies less than five metres above mean sea level, the average height of the sea. Sea levels around the country could rise by up to 1.15 metres by 2100. Singapore's compact geography leaves little room to move inland, making protection of its existing coastline a central planning priority.

The plans extend beyond keeping seawater out. Raised paths could carry cyclists and pedestrians, new land could support homes and parks, and the proposed Long Island development could create Singapore's 18th reservoir. Along sensitive stretches of shore, the placement of defences will also determine how much room remains for beaches, seagrass and other coastal habitats.

As of August 31, 2025, detailed engineering and environmental impact assessments remain ahead. The proposals are designed to be adjusted as planning develops, with construction introduced in phases to manage cost and sustainability. The immediate task is to turn a broad coastal protection strategy into designs that fit each stretch of shoreline.

Why the Sea Level Record Matters

Singapore's planning is taking place alongside research suggesting that the surrounding region has been responding to rising seas for longer than previously understood. Studies of coral fossils from the Indian Ocean indicate that sea level rise there began accelerating as early as 1959.

Global warming and changing wind patterns have driven that acceleration. The findings give planners a longer record against which to consider changes already visible along coastlines, alongside projections for the rest of this century.

Professor Paul Kench of the National University of Singapore explained that the effects have been accumulating for decades:

The Indian Ocean and South-east Asia have been responding to sea level rise for 70 years already. A lot of the physical changes we see in the landscapes over the decades have already been induced by sea level rise.

For Singapore, the challenge involves both the gradual rise in sea level and episodes when seawater reaches unusually high levels. Storm surges and extreme high tides are among the conditions the proposed barriers and gates are intended to address. A storm surge is a rise in seawater associated with a storm, adding to the water level coastal defences must withstand.

How Barriers and Tidal Gates Would Work

PUB's proposed coastal barriers would use large structures resembling arms, fitted with gates that can open or close according to weather and tidal conditions. Three barriers are planned to connect Sentosa Island to Pulau Brani and the mainland, forming a shield against storm surges and high tides.

The barriers would remain open most of the time, preserving sea views and allowing maritime activity to continue. They would close when needed to keep unusually high seawater from reaching the areas behind them.

Tidal gates at canal outlets would perform a related task. Under normal conditions, they would remain open to allow maritime activities and limit environmental disruption. During high tides and extreme weather, they would close to stop seawater entering inland areas through the canals.

Singapore's approach draws on examples including the Thames Barrier in the United Kingdom and the Maeslantkering in the Netherlands. Both have protected low coastal cities against catastrophic flooding. Singapore must adapt that approach to its own dense urban development, limited land and tropical climate.

The continuous defence line would therefore use different structures in different places. Barriers and gates would protect openings through which seawater could enter, while raised land, embankments and stronger shoreline structures would protect other stretches of coast.

Higher Shorelines With Space for Everyday Use

Changi Beach Park illustrates how a coastal defence can be placed behind the shore instead of directly along the water's edge. Raised platforms and bunds are planned further inland to preserve intertidal biodiversity and recreational access. The intertidal area is the part of the shore covered and uncovered as tides change.

A bund is a raised embankment that holds back water. In Singapore's plans, bunds could also serve as footpaths or cycling tracks, allowing the same structure to provide protection and a public amenity.

At Changi Beach Park, placing the defences inland would allow the beach to flood temporarily during extreme high tides while protecting areas behind the raised line. The approach is intended to maintain access and preserve shores rich in seagrass. Safety measures would be put in place for visitors during those events.

Elsewhere, PUB plans to upgrade existing shoreline defences and build or raise seawalls and revetments where necessary, particularly in Changi South and along the Greater Southern Waterfront. A revetment is a sloping structure that absorbs wave energy, helping protect the shore from the force of incoming water.

The choices depend on more than engineering strength. A defence must fit the available land, work with nearby development and account for the coastline's habitats and public uses. Footpaths, beaches and sea views are therefore part of the design discussion alongside flood protection.

Long Island Would Combine Land, Water and Protection

Long Island is one of the largest elements of Singapore's coastal strategy. First conceptualised in 1991 and revived in recent years, the proposal involves reclaiming about 800 hectares of land off East Coast Park, an area twice the size of Marina Bay.

The new land would act as a buffer against rising seas and storm surges, shielding the mainland from direct exposure. It would also create space for homes, recreational areas and amenities to support future population and economic growth.

A proposed reservoir would add another function. Long Island could create Singapore's 18th reservoir, linking coastal protection with water security. Around 20 kilometres of new waterfront parks and green spaces would provide additional places for recreation.

Site investigation works began in August, with marine surveys and soil sampling under way to inform detailed planning and design. Those investigations are part of the work needed to determine how the proposed reclamation and its associated infrastructure can be built.

Long Island brings several planning needs into one project: a barrier against the sea, a new water resource, land for development and more waterfront space. Its role in the coastal strategy is therefore broader than that of a seawall alone.

Protecting Habitats While Choosing Where to Build

PUB and its partner agencies must weigh technical feasibility and cost against environmental effects when choosing the position of coastal structures. A narrow channel may offer a less expensive place to build a barrier, yet it may also contain sensitive mangroves or rocky shores.

Environmental impact assessments and engagement with residents, nature groups and businesses are intended to help shape those decisions. The placement of raised protection behind Changi Beach Park shows how a design can leave room for a living shoreline while protecting land further inland.

Mangroves, seagrass meadows and coral reefs also have roles in coastal resilience. Mangrove forests can trap sediment and keep pace with rising seas, while seagrass and reefs help buffer wave energy and support biodiversity. These natural systems can complement the engineered structures forming the backbone of Singapore's defences.

Research into ancient coral microatolls is helping scientists understand how coastal ecosystems have responded to sea level changes over decades. That longer record can inform thinking about how habitats may contribute to future protection.

Professor Adam Switzer, a coastal science expert at Nanyang Technological University, described the value of combining traditional field data with modern modelling:

New sea level insights from coral records like these are helping South-east Asia and Singapore sharpen climate models and unlock smarter, nature-based solutions, like reef and mangrove restoration, to build resilient coastlines for the future.

The planning task is to combine those ecological functions with structures capable of protecting developed areas. Preserving habitats, maintaining public access and managing flood risk all affect where the eventual defence line can go.

Funding and Rules for a Century of Work

Singapore may need to spend up to $100 billion over the next century to safeguard its shores. That estimate reflects a programme extending well beyond the first construction projects expected in the 2030s.

The government has established a Coastal and Flood Protection Fund with an initial allocation of $10 billion. Annual budget allocations would supplement the fund, with government borrowing available if necessary to support the long programme of work.

Legislation is also being prepared. A Coastal Protection Bill is to be introduced in Parliament to define stakeholder responsibilities, enforce standards and safeguard land needed for protective measures. A code of practice for coastal protection is scheduled for launch by 2026.

Property owners are being encouraged to invest in flood resilience as well. The intended approach combines national infrastructure with action across society, rather than placing every protective measure along the water's edge.

Phased construction would allow Singapore to spread implementation over time while refining designs. The proposed flexibility matters for a programme that must respond to changing climate risks, practical engineering findings and the costs of protecting different stretches of coast.

Public Feedback and Digital Planning Tools

More than 3,000 people have participated in public consultations since 2024. Participants have supported proactive protection and offered ideas about how the defences should fit into daily life.

The government has incorporated feedback on preserving sea views, maintaining public access and adding recreational features. Those priorities help explain proposals such as barriers that remain open under normal conditions and embankments that double as paths.

Technology is another part of the planning effort. Advanced monitoring systems, digital twins and analysis of data as it arrives are being explored to forecast floods, simulate extreme weather and refine the design of engineered and natural protection measures.

A digital twin is a virtual model of physical infrastructure. In this work, such models can help planners examine how proposed structures may perform under different conditions before committing to a final design.

The aim is to keep the strategy responsive to new information. Monitoring, simulations and consultation each contribute something different: measurements of changing conditions, tests of possible designs and an understanding of how people use the coast.

Coastal Protection Meets New Urban Development

Changi Airport Terminal 5 will include an elevated airfield as part of its flood resilience strategy. Along the shoreline, cycling paths may be raised so that routes used for recreation also serve as coastal defences.

The Greater Southern Waterfront will bring together new residential, commercial and green spaces with shoreline upgrades. Its development links future uses of the coast with the infrastructure needed to protect them.

These projects show why Singapore is treating coastal protection as part of urban planning. Decisions about the height of land, the position of paths and the design of waterfront neighbourhoods can all contribute to managing rising seas.

The same approach runs through Long Island and Changi Beach Park: combine protection with other uses where possible, while accounting for the environmental and practical constraints of each place. Singapore's experience offers lessons for other coastal cities balancing development with climate adaptation.

From Early Proposals to Construction in the 2030s

Singapore's coastal programme connects research reaching back decades with construction and protection extending far into the future. The main dates show how the scientific record, public planning and proposed works fit together:

• 1959: Coral fossil studies indicate that sea level rise in the Indian Ocean began accelerating as early as this year.
• 1991: Long Island was first conceptualised.
• Since 2024: More than 3,000 people have participated in public consultations.
• August 2025: Site investigation works for Long Island began, including marine surveys and soil sampling.
• By 2026: A coastal protection code of practice is scheduled for launch.
• The 2030s: Construction of major coastal defences is targeted to begin, followed by phased implementation.
• 2100: Sea levels around Singapore could be up to 1.15 metres higher.

The next stages include detailed engineering, environmental assessments and further refinement of the proposals. Across the programme, Singapore is seeking to preserve a usable, liveable waterfront while building the protection its limited land area requires.

Key Points

• About 30 percent of Singapore's land is less than five metres above mean sea level.
• A four-year, S$18 million study underpins proposed defences from Pasir Panjang Ferry Terminal to Changi.
• Three coastal barriers, tidal gates, raised platforms, bunds, seawalls and revetments would form a continuous protection line.
• Long Island would reclaim about 800 hectares, create Singapore's 18th reservoir and add around 20 kilometres of waterfront parks and green spaces.
• Environmental assessments and public feedback will help shape designs, including protection for habitats and public access.
• The government has set aside an initial $10 billion in a dedicated fund, against estimated needs of up to $100 billion over the next century.
• A Coastal Protection Bill is planned, a code of practice is due by 2026 and construction is targeted to begin in the 2030s.