PUB explores groundwater in western and southern Singapore

AsiaOne 26 Apr 13;

SINGAPORE - National water agency PUB is looking into the potential of tapping underground water sources.

The agency said on Friday that it has called a tender for consultancy services to study the potential of tapping aquifers and other underground water sources in the western and southern parts of the island, in an area known as the Jurong Formation.

The three-year Groundwater resource assessment in Jurong Formation study will be awarded in July 2013.

Here is the press release from PUB:

SINGAPORE - National water agency PUB has called a tender for consultancy services to study the potential of tapping aquifersand other underground water sources in the western and southern part of the island, in an area known as the Jurong Formation.

Titled "Groundwater resource assessment in Jurong Formation", this three year study will be awarded in July 2013.

The study comprises three key areas:

a. Development of groundwater flow model of Jurong Formation
b. Field Investigation Programme
c. Validation Study

Over the last 50 years, through integrated water management, and investments in R&D, PUB has put in place a long - term water supply strategy called the Four National Taps.

The Four National Taps comprise local catchment water, imported water, ultra-clean, high-grade reclaimed water branded as NEWater, and desalinated water.

The Four National Taps has ensured a robust and sustainable water supply for Singapore. Singapore's water demand currently stands at approximately 400 million gallons a day (mgd), and is projected to almost double by 2060.

With competing demands for land for other uses such as housing, industries and other services, it will be increasingly challenging to build new reservoirs to meet our water needs. To enhance the long term sustainability of Singapore's water resources, PUB is always on the lookout for new water sources.

There are potential solutions in the form of naturally occurring aquifers and groundwater.

"Through this study, we are exploring the presence of deep aquifers within Singapore's geology and if it is possible for us to tap on this water source," said Mr Harry Seah, PUB's Chief Technology Officer.

"However, the extraction of groundwater will only be carried out if the risks of groundwater extraction can be adequately managed with no impact on existing buildings and infrastructure, which will be verified by the groundwater models to be developed through this work." he added.

Despite its small size, Singapore's geology is thought to be complex, spanning rocks hundreds of millions of years in age to more recent soils and sediments.

At the surface, the Bukit Timah Granite is seen in the central and northern regions, sedimentary rocks of the Jurong Formation are seen in the western and southern regions, and old alluvium is seen in the eastern region.

Based on knowledge of other rock formations worldwide, and from observations made during engineering work , it may be possible that the Jurong Formation could host a deep, confined aquifer which could be less prone to surface pollution or subsidence.

Singapore's geological setting indicates that there are other groundwater prospects, each with their specific advantages and challenges. This includes unconfined aquifers in the Old Alluvium, fractured rock in the Bukit Timah Granite, and confined aquifers in other rock formations of Singapore.

Besides Singapore's main is land, PUB has embarked on a study to verify the feasibility of extracting groundwater from reclaimed land in Jurong Island.

The R& D project entails assessing the potential yield and quality of groundwater, and the necessary groundwater management measures to prevent any land subsidence due to groundwater extraction. The project has been awarded and has commenced in April 2013.

PUB is in the midst of finalising the appoint ment of an international Expert Panel on Hydrogeology to give guidance and direction on its underground water exploration endeavours.

"This is Singapore's first foray in the search for deep aquifers . Besides exte nsive examination of our underground geology, we also want to learn from and tap on the expertise of overseas experts who have vast experience studying and carrying out groundwater exploration work in other countries," said Mr Seah.

The Expert Panel will convene at least once a year to discuss and provide advice on the two groundwater projects and any other related matters on hydrogeology.

Singapore’s fifth ‘national tap’ may draw on groundwater
Eugene Neubronner Today Online 27 Apr 13;

SINGAPORE — Looking to add a fifth “national tap” to Singapore’s existing four, national water agency PUB announced yesterday that it was looking to study the possibility of drawing on “naturally occurring aquifers and groundwater” in the area of the Jurong Formation.

Aquifers are underground layers of water-bearing permeable rock or unconsolidated materials, such as sand, from which groundwater can be extracted.

The PUB has called a three-year consultancy services tender to study the potential of tapping on aquifers and other underground water sources in the western and southern part of the island, which contain rock deposits called the Jurong Formation.

The study will look at the development of groundwater flow models, field investigation programmes and validation studies.

The tender will be awarded in July. PUB declined to review the budget for the study.

Singapore’s current four “taps” are the local catchment areas, imported water, desalinated water and reclaimed water, known as NEWater.

The PUB said that water demand here will nearly double by 2060 — from about 400 million gallons a day currently — of which about 70 per cent of demand will come from the non-domestic sector.

With “competing demands for land”, the PUB said, it would be “challenging” to build new reservoirs to meet Singapore’s water needs.

“Based on knowledge of other rock formations worldwide and from observations made during engineering work, it may be possible that the Jurong Formation could host a deep, confined aquifer which could be less prone to surface pollution or subsidence,” the PUB said.

The agency noted that advances in geophysical exploration methods over the last few decades make surveying today “more effective than in the past” and will help in the study.

PUB Chief Technology Officer Harry Seah said “extraction of groundwater will only be carried out if the risks of groundwater extraction can be adequately managed with no impact on existing buildings and infrastructure.”

This will be verified by the models that will be developed in the study, he added.

Academics TODAY spoke to said such aquifers would probably be at depths of 50 to 100 metres.

Earth Observatory of Singapore Director Kerry Sieh suggested three areas the study is likely to look at: Porosity, permeability and fracturing.

Porosity is the amount of space for water to flow in while permeability is how easily water can flow. Fracturing is when rocks are broken up with enough spaces in between for water to accumulate.

“The next question would then be, is there enough water to pump it out?” he said.

Assistant Professor Chew Soon Hoe from the Department of Civil and Environmental Engineering at the National University of Singapore pointed out the challenges the study would have to address if they do indeed strike gold.

“How would you recharge the amount of water that goes back in?” he asked. “And how do you make the well pumping economical?”

Dr Sieh also echoed some of these concerns. He gave the example of India’s river Ganges, which has had so much water pulled out it is “measured in dropping meters per year”. Singapore, like elsewhere, will have to ensure that such sources are tapped “sustainably”.

The PUB has also embarked on a study to verify the feasibility of extracting groundwater from reclaimed land in Jurong Island. The project has been awarded and commenced earlier this month.

Additionally, the PUB is finalising the appointment of an international expert panel on hydrogeology to “give guidance and direction on its underground water exploration endeavours”.


More about PUB’s tender
Today Online 27 Apr 13;

What is an aquifer?

An underground layer of water-bearing permeable rock. There are two kinds: Confined and unconfined. Confined aquifers are typically deeper and separated from the surface by a low-permeability layer.

How will we get the water?

Most likely by using pumping stations to suck the water out like a straw.

Why is the PUB doing this now?

Water usage here is expected to almost double by 2060 from approximately 400 million gallons a day today. While the PUB has been aware of some amount of surface groundwater, it is now looking at confined aquifers through a comprehensive study.

Which other countries are doing this?

Most countries tap on groundwater for their freshwater needs. Queensland and parts of South Australia, for example, tap on the Great Artesian Basin, one of the largest ground aquifers in the world.

PUB calls for tender on studying groundwater potential
Maryam Mokhtar Straits Times 27 Apr 13;

NATIONAL water agency PUB has called a tender for consultancy services to study the potential of tapping underground water sources in the western and southern parts of Singapore, it said in a press release yesterday.

The area to be studied is part of the Jurong Formation, a bedrock of sandstone, siltstone, mudstone, shale and limestone.

The three-year study, to be awarded in July, will assess if the water stored deep in the pores and crevices of these sedimentary rocks can be harnessed and used.

Built on the 230-million- year-old Jurong Formation are areas like Jurong, Clementi, Bukit Merah, and Choa Chu Kang.

The study will comprise the development of a groundwater flow model, field investigations and a validation study.

"Through this, we are exploring the presence of deep aquifers within Singapore's geology and if it is possible for us to tap this water source," said Mr Harry Seah, PUB's chief technology officer.

Aside from homes using well water in the past, Singapore has not tapped underground sources on a larger scale. Groundwater is significant for countries such as the United States, China, and Saudi Arabia.

Mr Seah noted that the extraction of groundwater would be carried out only if the risks of extraction can be managed and there is no impact on existing buildings and infrastructure.

The rock formations in Singapore are "significantly large" and technically, have the potential for extracting groundwater, said Mr Chong Kee Sen, vice-president of the Institution of Engineers, Singapore (IES). He added that in IES' view, the studies should take into account the potential impact on land stability and subsidence and consider factors such as changes in groundwater flow that could be critical to grassland or wetland habitats.

Singapore's water demand currently stands at approximately 400 million gallons a day and the figure could almost double by 2060 - enough to fill more than 1,200 Olympic-size swimming pools a day.

The country's water sources comprise imported water, treated rainwater and sea water, and reclaimed used water.

PUB also embarked on a study this month to see if groundwater can be extracted from reclaimed land in Jurong Island.

In 2010, PUB found the island had fresh groundwater, after it dug a 5m-deep well and pumped a litre of water per second from it for three months.