Ready and Easily Available
DR Azuhan Mohamad, of the Institute of Geology, who has been in the business for over 25 years, has quite a bit to say about underground water.
Q: What’s the difference between groundwater and surface water?
A: They are the same. In terms of volume, studies done by Unesco show that 95 per cent of fresh water resources are underground.
Q: How long does it take to extract groundwater and to have a system in place?
A: One or two weeks to extract, and three to four months to construct the system, depending on how comprehensive it is and how far the water is pumped.
However, geological studies to locate the groundwater areas take longer.
If it’s sandy alluvium like the Kelantan or Terengganu river basin, you can strike water almost everywhere.
For a limestone area like Kuala Lumpur, water comes from the cracks and fissures in hard rocks. These cracks are interlinked and promise a lot of water, unless they are filled with sediments.
Q: Is extracting groundwater from cracks difficult?
A: Very difficult, compared to extracting water from sandy alluvium. A lot of geological studies need to be done to determine where the cracks are and what kind of bedrock they are.
Normally, the best formation is the limestone but pumping too much water can lead to cavity and induce sinkholes.
Q: Do we have the technological means to extract groundwater?
A: Yes, there are established water operators which have been around for more than 30 years.
Kota Baru has been 100 per cent dependent on groundwater for ages.
Q: How much groundwater can we extract?
A: Studies show that 400 million litres per day are available from the Langat basin but we are only taking 50 million litres per day.
I think we can take out the exact amount that goes into the land, as the Langat basin is a short-term measure for droughts. Even if it’s for long term, we can artificially recharge the aquifer.
Q: How do you artificially recharge it?
A: One way is to do a recharge basin. During a rainy or high runoff period, instead of letting the water go into the sea, we can pump surface water from rivers and store it into a recharge basin, and let this water artificially seep into the ground.
The other method is to use the recharge well, where wells are filled with very clean water. The recharge basin is better, as the soil acts as a sieve for dirty water.
Q: Have there been studies on how viable groundwater is for the mass population?
A: Studies have been done in patches, because it’s expensive to do groundwater studies due to the drilling involved.
Q: What has happened to groundwater development in the past five years?
A: Not much in terms of exploration because it has already been done by the Minerals and Geoscience Department and the Rural and Regional Development Ministry.
Also, geologists find it hard to convince our water supply engineers about the significance of groundwater.
Q: Are dams sufficient in meeting our needs?
A: Dams have become inefficient. Dams are filled not just with water, but also silt and sediment. The Sultan Abu Bakar hydroelectric dam in Cameron Highlands had to be rehabilitated for this reason.
The vast surface also increases evaporation rate to between four and eight millimetres per day. When that’s multiplied by thousands of hectares, a lot is lost.
Q: What are the pros and cons in extracting groundwater?
A: Groundwater has better quality, the temperature is constant and it can be obtained on site.
However, once contaminated, groundwater is very hard to clean up. It can also lead to land subsidence and saline intrusion.
Once groundwater is extracted, the pressure in the ground becomes very low, causing seawater to seep in and wells to turn salty.
Q: How does land subsidence happen?
A: The problem of subsidence with groundwater development is due to uncontrolled development, such as in Bangkok.
Sinking will only happen in alluvium base. Bangkok has 15 metres of clay, underneath of which there is a 100 metres sand layer.
Pumping too much water from the sand caused water from the clay to leak into the sand below.
To make matters worse, there are more than 10,000 wells in Bangkok. In Selangor, there are only about 100 wells. We have yet to face this problem.
Q: So, an alluvium base has more tendency to sink than limestone?
A: Yes. For alluvium, the thicker the clay, the more land will subside.
Q: Will people have to pay the government for their wells?
A: In Selangor, only industrial users are charged. They extract less than five million gallons per day.
Q: How much do we have to pay for groundwater if it’s made available?
A: Groundwater is less expensive and easier to develop. Water rates in Kota Baru are one of the lowest.
This is because groundwater development is a decentralised system where it can be developed at the source and piping is shorter. If the water’s from a green area, there’s even no need for treatment.
Q: Will groundwater be available any time soon?
A: Yes, if there is a political will. Sometimes, we don’t see the need for it because rainwater is easily obtained.
Q: How dependent should we be on surface and groundwater?
A: We cannot be 100 per cent dependent on surface water as it is dictated by the weather. Groundwater must be made an alternative source during the dry season.
The problem is once a water crisis is over and the weather improves, we tend to forget the hardship we have faced.
Q: How do you determine groundwater areas?
A: We have to study the geology of the land. Alluvium has the most potential, followed by limestone and granite. But to be really sure, we have to drill.
For example, I’ve built two wells in Perlis just 30 metres apart. One is dry, the other has water coming right up to the surface.
Q: Whose jurisdiction does the groundwater come under?
A: It comes under the state government.
Q: How do we extract groundwater?
A: Drill and construct a well. If it’s an alluvium aquifer, there must be a screen to trap the sand.
For hard rocks, there is no need for a screen but it’s harder to drill into them. Next, use an electricity or solar powered pump to extract the water.
Run a test on the quality of the water. If it’s not clean, construct a treatment plant. Otherwise, it can be delivered straight to the users.
Q: How much groundwater do we have?
A: About 5,000 billion cubic metres in storage, which makes up 90 per cent of our freshwater resources. We have more than enough, but it’s not easy to strike an aquifer.
Q: At the rate we are using our water, how long will this last us?
A: That’s not a problem at all. Water shortages are not due to lack of resources, but mismanagement.
In 2005, the water demand for Peninsular Malaysia was 10,321 million litres per day, which was only 2.5 per cent of our surface water.
The projection for 2010 is 14,217 million litre per day, or 3.4 per cent of surface water. We are using very little of what we have in dams and rivers. But due to mismanagement, a lot is lost.
That’s why regulators like the National Water Commission and Water Asset Management Company have been set up to look into the infrastructure.
Q: Who’s responsible?
A: There is a lack of political will.
For Kelantan and Terengganu, no money is pumped back into the industry for development because water operators have no control over the revenue.
(c) 2007 New Straits Times. Provided by ProQuest Information and Learning. All rights Reserved.