The underground has been increasingly recognized as an important resource and part of the solutions to meet the needs for sustainable urban development. However, despite its promise and many benefits, the use of underground space has tended to be the last resort, due to high development cost and the complexities and challenges in its planning and development. Underground space development is complex because of the large size and budget of the development, the multi-disciplined nature of such projects, the long lead time in the planning and development, and the large number of and often diverse types of components or subsystems and stakeholders. The dynamic nature involving multiple time scales, which often outlive the technology cycle time, means that the requirements often change with geopolitical events and other economic and social development in society. Amidst such complexities, the task is often made even more difficult due to lack of long-term planning and coordination which results in high cost due to many constraints and construction in highly developed and congested urban settings.

While the use of underground space in Singapore has been largely driven by resource constraints such as land space and water, there are many major benefits for sustainable urban development. In 2010, the Economic Strategies Committee of the Singapore government made developing underground space part of the government’s long-term economic strategy with specific recommendations on master planning, geological investigations, investment in research and development, and addressing various legal and policy issues. With this, the use of underground space has been elevated to a strategic level and has become an economic imperative in resource-scarce Singapore.

Based on the experience of Singapore, this presentation discusses the key sustainability issues and the important roles that underground space can play in responding to these issues. It gives an overview of underground space use, recent developments, and future perspectives in Singapore, discusses key challenges, and examines possible strategies and key lessons for optimum use of underground space as part of Singapore’s sustainability efforts.