National water agency PUB looks underground for water storage solutions

The $950 million Jurong Rock Caverns, developed by JTC Corporation, that was opened in September 2014. PUB is exploring the possibility of using underground space for drainage and water storage. -- PHOTO: ST FILE 
The $950 million Jurong Rock Caverns, developed by JTC Corporation, that was opened in September 2014. PUB is exploring the possibility of using underground space for drainage and water storage. -- PHOTO: ST FILE 

SINGAPORE - National water agency PUB is exploring the possibility of using underground space for drainage and water storage as a way of helping the city better deal with the effects of climate change, such as more intense rain and prolonged dry spells.

If successful, the use of underground space will free up surface space while still being able to add to Singapore's water storage capabilities.

These facilities, long championed by experts as a solution to mitigating the effects of climate change, can enhance the Republic's resilience against droughts, as excess water during periods of intense rain can be stored and used for dry spells.

The agency will do a 24-month study on the technical and economic feasibility of developing an integrated underground drainage and reservoir system.

The announcement was made by Minister for the Environment and Water Resources Vivian Balakrishnan at the start of the Singapore International Water Week Technology and Innovation Summit on Tuesday morning. The two-day event, which is being attended by more than 250 representatives from water industries around the world, will focus on research and development and is a prelude to the Singapore International Water Week 2016.

The study, slated to be completed in end-2017, will include geological surveys to obtain detailed information on soil and rock properties, and also look into the design options for an Underground Drainage and Reservoir System.

Soil and rock studies are crucial as the building of an underground reservoir will require suitable rock material. The data will also help experts determine the challenges involved in the construction of underground facilities.

The system is likely to have three key components: conveyance tunnels to channel stormwater, underground reservoir caverns for water storage, and a pumped hydropower system, which can convert potential energy from the flow of water from surface water bodies to underground caverns into clean energy. This energy can then be used to pump water in storage back up to the surface.

PUB said on Tuesday that this will "mitigate the impact of climate change and enhance resilience against droughts".

It added: "With limited land area of approximately 718 km2, Singapore faces a continuous challenge to come up with innovative solutions to create spaces for a range of uses, while keeping Singapore highly liveable."

PUB's Director of Policy and Planning William Yeo said: "Besides allowing us to overcome land limitations for key drainage and water storage infrastructure, the study can potentially allow us to mitigate the impact of climate change and flood risks, and strengthen the overall drought resilience of Singapore's water supply."

Mr Yeo also assured the public that PUB will work with relevant agencies and stakeholders to ensure that the geological surveys are "conducted with care and sensitivity to the environment".

The findings from the study will allow PUB to decide whether the Underground Drainage and Reservoir System can be pursued further.

Singapore has already gone underground for the storage of oil, as well as military munitions and explosives. The $950 million Jurong Rock Caverns, developed by JTC Corporation, was opened in September 2014, while the Singapore Armed Forces Underground Ammunition Facility was opened in 2008.