Comprehensive modelling studies lay the foundation for flood risk mitigation, biodiversity conservation and sustainable infrastructure development 

Climate change is driving sea level rise and more intense rainfall, increasing flood risks in both coastal and inland areas. As part of its national climate adaptation strategy, the Singapore Government initiated site-specific studies to assess these risks and guide the engineering design of adaptation solutions. This builds on earlier work such as the Coastal Adaptation Study (2013–2019), undertaken by Surbana Jurong in partnership with DHI, which laid the foundation for Singapore’s long-term coastal protection efforts. 

DHI has since contributed to three of the site-specific projects under this strategy, focusing on safeguarding the nation’s freshwater supply, industrial and manufacturing hubs as well as maritime facilities. The scope included high-resolution modelling of long-term coastal flood risks — driven by sea level rise, storm surge, wave action and rainfall — paired with high-level environmental assessments to flag potential showstoppers in the protection options under consideration. Together, these solutions establish a resilient, cost-effective and environmentally sustainable foundation to support Singapore’s climate adaptation planning — both now and into the future.

Challenge

Flood risks pose a significant threat to local communities in Singapore. In extreme scenarios, these risks could disrupt critical national functions such as water supply, industrial operations and maritime activities on offshore facilities — leading to economic losses, operational downtime and long-term challenges for national resilience planning.

Infrastructure development in response to these risks must be carefully managed to serve its intended functions for coastal protection, while preventing habitat loss, biodiversity declines and disruption of ecosystem services. Protecting ecological integrity is key to ensuring that climate adaptation measures remain sustainable and do not create new vulnerabilities over time.

Adding to the complexity, the challenge lies in designing adaptive and sustainable solutions that effectively balance climate risk mitigation with economic viability, while considering the unique context and requirements of each project:

• Water quality and biodiversity considerations along northwest coast 
  Wave overtopping estimation and seepage modelling are crucial considerations for assessing water quality in freshwater reservoirs along Singapore’s northwest coast. The area also calls for thorough environmental evaluation to safeguard ecosystem protection while planning and developing coastal protection measures.
• Complex drainage infrastructure on Jurong Island 
  Jurong Island features a complex drainage network encompassing the original landforms and reclaimed catchments, with contributions from rainfall-runoff and industrial discharges. Accurate modelling of these components is essential to assess flood risks and develop effective climate adaptation measures, while minimising operational disruptions.
• Multi-stakeholder engagement on protection planning for selected offshore islands 
  These selected offshore islands, managed by MPA, support maritime operations and require a tailored flood protection approach. Close coordination with stakeholders and agencies like PUB was essential to align design approach with both operational needs and climate resilience. 

Solution

Collaborating closely with clients, DHI applied advanced numerical models and international standards to assess both coastal and inland flood risks, in view of climate change. 

Solution highlights:

• Assessment of long-term coastal flood risks: Evaluating extreme tide-surge levels and environmental waves/ship wake, including joint occurrence probabilities, to support overtopping calculation and flood modelling for planning and design.
• High-resolution flood modelling: Conducting detailed simulations of flood depths and inundation extents across various climate scenarios using site-specific data, enabling precise risk assessments and the design of targeted, cost-effective adaptation measures.
• High-level environmental study: Performing impact modelling, habitat mapping and evaluation of potential effects from proposed adaptation options to ensure they are environmentally sustainable and aligned with biodiversity goals, while serving its function as coastal protection against flood risks.
  

What sets this solution apart is its integrated approach that seamlessly combines advanced numerical modelling with scenario-based framework and high-level environmental studies. By coupling 2D and 3D hydrodynamic models with agent-based modelling, sediment transport and groundwater simulation, the solution provides a holistic, data-driven foundation for climate adaptation planning that addresses flood risks, protects biodiversity and supports sustainable infrastructure development.