Monica Kotwani Channel NewsAsia 24 May 13;
SINGAPORE: Experts said finding underground reservoirs of water could solve Singapore's problem of not having enough space to hold rainwater, and it could also prove to be the country's fifth tap.
The comment follows a recent tender called by national water agency PUB to study the feasibility of extracting groundwater from the southern and western parts of Singapore.
If the three-year study shows promise, Singapore could join a host of countries that source drinking water from the ground.
Groundwater could then add to Singapore's water supply that now depends on four sources -- imported water, catchment water, treated recycled water and desalinated water.
The four sources are referred to as the "four national taps". These sources provide for the nation's current water demand of some 400 million gallons of water each day. PUB said this number is projected to almost double by 2060.
Currently, the area under scrutiny is a 200-million-year-old land space called the Jurong Formation.
Dr Grahame John Henderson Oliver, a geologist and senior lecturer with the National University of Singapore, said: "The Jurong Formation in the west of the island is made up of porous rocks -- lots of sandstone. They know there is water going through the rocks. The next question is: 'How much water?' The next question after that: 'Is it drinkable?'"
Experts also hope the study will show how water can be extracted from these aquifers, also known as underground reservoirs, sustainably.
Associate Professor Tan Soon Keat, deputy director of the Nanyang Environment and Water Research Institute at Nanyang Technological University, said that if water is removed and not replenished, it could lead to the land subsiding.
"Because of this void being empty, the soil particles come together, occupying a more compact surface. If you look at a wide expanse of an area, the compaction of the surfaces means that it has to go downwards -- the ground surface has to settle down to occupy the space that has been emptied out," added Assoc Prof Tan.
Recharging the ground with water can avert the problem. To sustain water extraction from the reclaimed land and from deeper in the aquifers would mean creating a cycle -- pumping water out at one end, and allowing rainfall to replace it while giving time for the groundwater to be naturally cleaned before being pumped out again.
"If we can establish an aquifer, and through our engineering contributions, develop it into a sustainable water source -- in an island state like this, I think it will be something exciting to do," said Assoc Prof Tan.
The Jurong Formation could be just one source -- the Old Aluvium is a 100-million-year-old formation in eastern Singapore.
Geologists said this formation is made of sand and gravel, and based on geological studies in similar formations elsewhere, its potential to hold groundwater can be even greater.
- CNA/ac
