In Singapore, while direct hits from tropical cyclones are rare, the city remains vulnerable to flooding from storm surges originating in the South China Sea or monsoon winds, compounded by frequent intense rainfall and high tides.

Coastal adaptation studies are underway in many cities around the world, with a range of strategies being explored. For densely populated cities like Hong Kong and Singapore, where land scarcity constrains spatial flexibility, certain measures such as retreat are far less feasible. This underscores the importance of place-based solutions that reflect each city’s unique physical and social context.  

Harnessing the power of big data, advanced modelling, and artificial intelligence  

Engineering solutions to these challenges are increasingly informed by big data, advanced modelling tools, and artificial intelligence. ECMWF ERA5, globally regarded as a reliable atmospheric and oceanic reanalysis dataset, is extensively used at SJ Group (SJ) to inform coastal models and high-level coastal hazards analysis.   

In engineering designs, data is often required at a spatial resolution much finer than that of the global dataset, and downscaling of data by coastal and inland models is necessary. For flood modelling, the challenge is at the land-sea interface, where inland flooding due to intense rainfall interacts with storm surge from the coast. SJ, in collaboration with the Nanyang Technological University (NTU), has pioneered approaches such as the Compound Flood Model, which integrates coastal storm surge data with inland rainfall runoff models to address compound flooding risks. For example, coupling two different modelling tools, one that simulates storm surges from the sea (Delft3D) and another that models rainfall-induced flooding (PCSWMM), allows engineers to forecast and evaluate scenarios where inland and coastal floods interact. These scenarios are not additive; instead, the interplay of factors can amplify flood impacts beyond the sum of their individual contributions. 

A practical application of this approach was demonstrated in the Philippines, where the time-varying storm surge induced by Typhoon Haiyan (2013) was simulated using a coastal model. By combining this with the inland flooding due to the storm induced rainfall, we were able to determine the flood inundation depth and extent of this devastating storm event.

While these numerical modelling tools have been providing reliable results and are now the de facto standard in coastal engineering design, challenges remain in predicting unusual and extreme events. For example, Typhoon Saola (2023) was initially forecast to bring a large storm surge to Hong Kong and Macau, but weakened unexpectedly, resulting in minor coastal flooding, while inland flooding from rainfall proved more severe than anticipated. This highlights the limitations of traditional models in capturing the full scope of extreme events. 

Heung Fa Chuen flooding after Typhoon Hato (2017) 

To address these gaps, researchers are actively exploring the use of artificial intelligence (AI) in forecasting extreme events with some promising early results. Although not yet a sufficiently reliable tool in coastal engineering design, AI has the potential to play a transformative role in the near future, and developments in this area are being closely monitored.

Engineering solutions in practice 

When it comes to mitigating coastal hazards, a multi-disciplinary approach and engineering ingenuity are critical. 

Hard infrastructure

Hard engineering structures such as slope revetments and seawalls remain a staple of coastal defence, designed to protect coastal communities and infrastructure from high tide and storm surge and minimise wave overtopping. With the foreseeable climate change in future, incorporating climate change factors into designs has become a norm. For example, Singapore’s National Water Agency (PUB) regularly reviews the platform level and coastal protection level of Singapore’s new developments with the latest projection of climate change. Site-specific coastal adaptation studies by PUB, in which SJ is actively involved, will undoubtedly be important references in future decision-making processes.  

Nature-based solutions

Living shorelines and nature-based solutions represent a shift towards sustainable engineering. By integrating vegetation, oyster reefs, and natural materials, these solutions reduce erosion, encourage sediment accretion while enhancing biodiversity. In Singapore, for example, mangroves are being rehabilitated along selected coastlines to act as natural storm barriers, dissipating wave energy and providing habitat for marine life. SJ is currently involved in shoreline protection projects that incorporate these nature-based measures.  

Tidal gates and reservoirs

Coastal reservoirs with tidal gates, such as Singapore’s Marina Barrage, serve as multifunctional defenses, supporting not only flood control but also water supply and recreation. These systems rely on precision-engineered designs that consider time-varying water levels to optimise performance during storm surges. Such measures are already in use in various places in Singapore and have been considered in some site-specific coastal adaptation studies in Singapore. However, a study by SJ (Zhao et al., 2024) indicated that the effectiveness of the tidal gate will diminish over time as sea levels rise, due to a decreasing head difference between the coastal reservoir and the sea. To maintain normal operation, a pump will eventually be required to increase the reservoir head. 

Strategic long-term planning: the path to resilience 

Engineering solutions must align with long-term strategies. In Singapore, this includes site-specific coastal adaptation studies that evaluate unique risks along different segments of the coastline. These studies require multi-disciplinary efforts to carry out inception studies, flood risk assessments, pathway development, cost-benefit analysis and environmental studies, before a preliminary design can be derived. The result is a nuanced understanding of the best coastal adaptation solution and pathway that evolves with the future climate change projections. 

Digital tools are also helping drive smarter planning. SJ and SMEC in collaboration with NTU, have developed interactive flood risk dashboards that overlay flood models with GIS data. These platforms provide decision-makers with a holistic view of flood risk, enabling informed infrastructure planning. These platforms are particularly valuable for integrating social, environmental, and economic considerations into disaster risk reduction strategies.

Accelerating engineering solutions for coastal resilience 

For engineers, the challenge of coastal resilience is as much an opportunity as it is a test of ingenuity. Through advanced modelling, innovative infrastructure designs, and long-term planning, we can not only mitigate the impacts of coastal hazards but also build smarter, more adaptive communities. 

Hong Kong, Singapore, and other coastal cities are proving grounds for the future of resilience engineering. By integrating hard science, innovative tools, and forward-thinking strategies, we can redefine the role of engineering in shaping a sustainable and climate-resilient future.