Can numerical modelling guide smarter coastal development decisions?

Singapore, a low-lying island nation with approximately 30% of its land less than 5 metres above mean sea level^[1], is highly susceptible to climate risks such as intensified rainfall, sea level rise, and high tides, all of which increase its flooding vulnerability. Extensive coastal developments including land reclamation, ports, and urban infrastructure require long-term, climate-informed strategies to safeguard resilience and manage costs.

This insights paper explores how integrating numerical modelling into coastal development decisions enables coastal cities such as Singapore address these challenges. By simulating complex processes such as tidal currents, waves, sediment transport, and water quality, advanced numerical models provide detailed, site-specific insights essential for effective planning. Incorporating climate projections into numerical simulations allows Singapore to assess future risks and test mitigation strategies, supporting the development of a sustainable, climate-resilient coastal infrastructure.

Key takeaways

• Numerical modelling is a flexible, cost-effective tool that should be used across all stages of coastal projects, providing insights that enhance planning and decision-making.
• Low-lying coastal cities like Singapore face serious climate risks, such as sea level rise and extreme weather, making early climate-informed planning essential for resilience and damage avoidance.
• Numerical modelling allows planners and engineers to explore multiple design scenarios and develop targeted, informed mitigation strategies that reduce damage and enhance resilience.

Singapore-specific climate projections and vulnerability

Recognising its climate vulnerabilities, Singapore has adopted a targeted approach to strengthen coastal and urban resilience. The Centre for Climate Research Singapore (CCRS) produces high-resolution climate projections for downstream use across multiple sectors, ensuring planning decisions are based on robust data.

Complementing this, Public Utilities Board (PUB), Singapore’s National Water Agency, conducts site-specific coastal studies to assess localised risks and evaluate tailored protection measures. These scientific efforts are supported by policy tools such as the Flood Resilient Development Guidebook^[2], to be launched by mid-2026, which will outline best practices for designing developments that can withstand flooding and adapt to changing climate conditions.

Numerical modelling is a flexible, cost-effective tool that should be used across all stages of coastal projects, providing insights that enhance planning and decision-making.

A key part of this strategy is numerical modelling, which enables planners and engineers to simulate future scenarios and develop suitable mitigation measures, and ensures Singapore’s coastal and urban infrastructure is both climate resilient and cost effective. The Long Island project is one example where modelling supports assessments of sea level rise and storm intensity, placing climate change considerations at the core of project planning.

This video shows current flow field around Singapore Island simulated using hydrodynamic model. The arrows indicate the direction of current flow, while the colour scale represents current speed magnitude, with blue/green areas indicating slower currents and orange/red indicating faster currents, particularly through the Singapore Strait.

Role of numerical modelling in resilience planning and design 

With recent advances in mathematical modelling and increased computational power, numerical models can now simulate coastal processes at higher spatial resolution and over extended simulation periods.

Numerical modelling is more cost-effective and flexible compared to field investigations, which cannot quantify or predict the changes to coastal hydrodynamics arising from new developments or future conditions. It allows the exploration of numerous design scenarios and the assessment of potential environmental impacts throughout the project lifecycle.

For instance, hydrodynamic model simulates flow dynamics in estuaries and tidal coastal areas, enabling assessment of change in current velocities and water levels under proposed coastal development such as reclamation. Local wave models simulate how waves transform as they move from offshore to nearshore zones, allowing evaluation of wave penetration and altered wave climates due to proposed coastal structures. Outputs from these models often feed into coupled sediment transport models to predict sediment movement and seabed changes, as well as water quality models to track pollutant dispersion.

Given its flexibility and broad coverage, numerical modelling supports not only climate-related studies but also a wide range of other applications across project phases.

Applications in coastal projects include:

Feasibility studies – Assess design viability and risks by modelling existing marine conditions (e.g., tides, currents, waves) to support preliminary decisions: for example, optimal placement of seawater intake and outfall structures.

Environmental impact assessments (EIA) – Quantify development impacts by comparing pre- and post-construction scenarios using hydrodynamic, wave, sediment transport, and water quality models. These analyses guide mitigation strategies to meet environmental standards.

Detailed design studies – Refine engineering parameters with high-resolution simulations to define design loads, optimise diffuser layouts for outfalls, and evaluate scour effects around structures.

Environmental management and monitoring plan (EMMP) – Support compliance during dredging and reclamation through sediment plume dispersion forecasts and hindcasts, informing early warning systems and the design of mitigation measures like silt curtains.

Post-construction monitoring – Numerical modelling is not commonly used for post-construction monitoring; however, marine biodiversity and environment quality monitoring is more commonly implemented at this stage. Through these functions, numerical modelling enhances the understanding and management of coastal systems, providing robust, site-specific insights that improve project sustainability and resilience.

Numerical simulations for EIA and Infrastructure Risk Assessment

Climate change considerations are not limited to EIA for new developments. Numerical modelling is also a vitally important tool for climate risk assessment and adaptation planning for coastal infrastructure.

In Singapore, coastal and marine projects are now expected to assess not only current impacts but also how climate change may alter those impacts throughout the project’s lifespan – from feasibility studies to EIAs and long-term operation. This reflects a broader shift towards resilience-based planning for long-lived coastal assets.

Traditionally, EIAs have focused on evaluating baseline environmental conditions and predicting immediate impacts of new developments under existing climate conditions. However, there is now growing emphasis on assessing potential impacts under future climate scenarios, reflecting heightened concerns from both authorities and the community about climate resilience.

Current practice can integrate projections from regional climate studies such as the V3 Report by the CCRS^[3]. These high-resolution projections, like sea-level rise, temperature changes, and change in weather patterns, can be incorporated into numerical modelling to assess how climate drivers could influence project-specific impacts.

This approach also supports cumulative impact assessments, evaluating how a project’s effects may interact with other developments in the area and with long-term climate change stressors.