Helping Singapore stem the tide

In this blog, Michael van de Watering, Coastal and Climate Change Adaptation Consultant at Royal HaskoningDHV, and Abhishek Saha, Senior Data Scientist at H2i, discussed how a coastal adaptation plan in Singapore is helping to stem the tide of climate change and associated sea level rise - and how this approach can be used as a leading example for other locations. In this blog, we look at that plan in detail.

Our disappearing coast

As sea levels continue to rise, and coastal communities face increasing risk, we’re met with a difficult truth: without intervention and adaption, our coastlines will soon not exist as they do today.

In the Asia Pacific region alone, this is likely to affect close to half a billion people, which means there’s no time to waste in planning for the future and taking concrete steps of incremental action. 

To mitigate and adapt to the impacts of climate change, careful planning is required to identify the level of risk and the correct measures to take in response.
The question at hand is simple, but vital: how do you increase climate resilience, protect biodiversity, dwellings, habitants, industries and infrastructure? And how do you plan and invest while facing future uncertainty?

Assessing the climate risk

Every coastal environment presents its own unique challenges. Singapore is a tropical island that experiences a large amount of rainfall, and this rainfall is likely to increase in volume and intensity as our climate changes.

Pluvial flooding, along with coastal floods associated with rising sea levels, are the two major sources of flooding in Singapore.

In fact, the country’s average sea level is now 14cm higher than pre-1970s levels, according to the Met Service. And this is a primary cause of concern for Singapore’s densely populated coastal zone. 

Despite this, Singapore’s 58km long southeast coast has not suffered a major flood for some time. But some smaller events in 2018 and 2020 have illustrated that there is a significant pluvial flood risk, and the impacts of higher sea levels are expected to become more frequent.

The government knows that the existing solutions designed to address these risks are no longer suitable. As a response, the Public Utility Board (PUB) has embarked on an ambitious climate change adaptation program. 

The program has three goals:

• Understand climate change
• Mitigate climate change
• Adapt to climate change

The first step of this program is to fully understand the climate risks involved. To that end Royal HaskoningDHV’s Global Flood Risk Tool has been used alongside flood risk modelling from H2i to monitor and predict flooding patterns in Singapore. 

Together, these applications model to predict flood hazards, flood damage, and overall flood risk, before helping to establish the most effective measures and adaptive pathways to mitigate those threats.

Inland and coastal models can be run separately or together to paint a holistic view of risk, and strategies are formed based on different scenarios of increasing severity. 

The interdependency of hydrological and coastal events or “joint probability” is then assessed in defining adaptation pathways. These pathways are designed to ensure that, over time, measures always comply with a national norm on flood safety. 

Royal HaskoningDHV is also using global climate change projections and scenarios to provide more detailed regional insights into the impacts Singapore is likely to face over the coming years.

Climate adaptation measures

When it comes to choosing the right measures to mitigate climate risks, a great number of aspects have to be considered – not least the most suitable ways to protect natural habitats, recreation areas, and sites of industrial importance that will be subject to future climate change impacts.

Climate adaptation measures therefore need to be mindful of what exists in various locations now, and the way people will want to use that land tomorrow. To do so they will need to be robust and allow for incremental changes in the future. 

Singapore is a particularly interesting use case in this regard, as the coast presents so many different environments, from urban seafronts to natural beaches and industrial ports. Singapore’s urban fabric is already greatly integrated and multi-functional, so the bar is set very high for future measures.

For this reason, the protection project has divided the coastline into eight hydraulically connected planning areas, each with different characteristics, and the most suitable solutions must be chosen for each area. That’s where our experience in providing numerous different integrated solutions and applying adaptive planning methods sets us apart.  

For instance, in natural areas, where biodiversity and wildlife play a primary role, our experience with nature-based approaches and solutions, including mangroves, living breakwaters, green dykes and coral reefs, is helping us to provide sustainable resilience measures that integrate seamlessly with the existing environment while making use of natural processes. 

In industrial and urban sectors, where solutions like sea walls, dykes, and dams are implemented, there are a different set of considerations.

Firstly, it is imperative for Singapore’s society that waterfront operations and recreation are not disrupted. While trade-offs are always to be expected to a certain extent, any future development of coastal protection is to include, maintain or improve on the current setting.
Secondly, aspects like liveability and aesthetics are essential and must be considered to make sure people can still enjoy coastal spaces. 

A large proportion of Singapore’s southeast coast is currently protected by “hard infrastructure” solutions, like sea walls. But the project is taking pains to ensure that these elements can fulfil secondary purposes, like boardwalks, presenting a pleasant urban experience that doubles as a protective measure.

Other examples include the conversion of a concrete canal into a natural waterway, that expands local park areas and also uses that expansion as a wetland to absorb and retain water in the instance of a flood.

The future of flood protection

The Singapore project includes a combination of engineering solutions, operational strategies, and predictive modelling to illustrate the whole gamut of coastal protection solutions available. 

Going forward, Royal HaskoningDHV hopes it can support the PUB with its global experience in climate adaption plans and help the country to become a leader in urban coastal protection, flood management research, climate adaptation and engineering services.

The project is a great example for other countries, and specifically mega metropolitain areas across the globe at risk from climate change, coastal inundation and pluvial flood concerns.