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Dr Eelco Lukas, a geohydrologist, is the Director of the Institute for Groundwater Studies at the University of the Free State (UFS).

Nearly two-thirds of South Africa depends solely or partially on groundwater for domestic needs, and in a water-stressed country this source is becoming increasingly important. But we need to use it wisely.

Dr Eelco Lukas, a geohydrologist, is the Director of the Institute for Groundwater Studies at the University of the Free State (UFS). He explains that all the natural water found in the earth’s subsurface is called groundwater. “When we look hard enough, we can find groundwater almost everywhere.  But that does not mean that we can start pumping groundwater at any location.  In many places, the amount of groundwater available (yield) is so little, or the water so deep that it is not financially viable to pump it.  Another problem might be the quality of the water.”

Numerous towns and communities depend solely on groundwater and many towns use a combined supply of surface and groundwater. When the town or settlement is far from any surface water and groundwater is available, boreholes are drilled. Depending on the size of the settlement, the boreholes are equipped with electrical or hand pumps.

Most of the big cities use surface water in their water pipes. Almost all big cities worldwide are located close to a supply of freshwater.  Cape Town has drilled many boreholes in the past two years to augment the city’s water supply.  However, problems can arise when a borehole is drilled for a community with a certain number of people, and soon there are more people than the borehole can supply for. It is not so much a case of the ‘borehole drying up’ but that the capacity has been exceeded.

Misconceptions about groundwater

With increasing drought and water restrictions being imposed, many people opted for their own borehole. When so many people draw water from the same source, the water table will drop. It can be compared to drinking a milkshake, but when five other people also drink with straws from the same milkshake, all will be left thirsty. 

Dr Lukas says because groundwater is something that cannot be seen with the naked eye, the general public has many misconceptions about groundwater. Some people think that you can drill a hole just anywhere and that you will find water, while others believe that water flows in underground rivers. It generally moves very slowly, only a few metres per year. And if it rains in a specific place, it does not mean that water will reach a particular borehole.

“Sustainable groundwater usage is the certainty that enough groundwater is available in years to come.  Sustainability is dependent on two external factors, namely demand and supply.  Unfortunately, both these factors are beyond the control of the geohydrologist.  When enough water is available for a community, the chances are that the community starts to grow, thereby enlarging the demand.  If the higher demand cannot be met, sustainability is no longer possible. When a change in rainfall pattern results in a decline of the precipitation, the groundwater recharge will become less, resulting in a lower supply of water.”


How does water move?

Groundwater moves through openings in the subsurface. These openings can be large (a millimetre to a few centimetres), but most of the time they are small, only a fraction of a millimetre. These are called pore spaces.  Water can only move through the pores if the pores are connected to other pores. The ease with which water can move through the rock is called hydraulic conductivity and is expressed in volume per area per time.  

Dr Lukas explains that different types of rock have different sizes of pore openings. The speed at which water can move through unconsolidated materials ranges from 1 000 m/d (gravel) to 10-8 m/d (clay). Consolidated materials range from 1 000 m/d (highly fractured rock) to 10-7 m/d (shale).  Sandstone, a rock that occurs in abundance in South Africa, has a typical hydraulic conductivity of 10-2 m/d, meaning that the speed at which the water flows is around 1 cm/d, which is less than 4 metres per year.  

In a way, you can compare groundwater flow to a pipe filled with marbles.  If you remove one marble at the one side, a marble may enter the pipe on the other side.  Although it may take the marble a long time to reach the other side of the pipe, the movement of the marbles is noticed almost immediately, says Dr Lukas.

Before groundwater is used, experts must make sure that it is suitable, Dr Lukas says. This is one of the areas that the Institute of Groundwater Studies at the UFS excels in. The institute also provides a complete service to industries through field investigations, the development of specialised field equipment, a well-equipped commercial and water research laboratory, and a number of computer models for the management of the aquifers, protecting them from pollution.

There are different standards for different purposes.  The best-known standard is the drinking 
water standard (SANS 241).  The water is tested for microbiology, as well as for the physical, aesthetic, operational and chemical determinants, and for the taste and colour.

There are several geophysical methods to locate groundwater.  “It must be stressed that the geophysical methods do not actually indicate places with water, but rather places where the geology and geological features support the presence of groundwater,” he says.

Different techniques are used to ‘look’ at different depths.   Water found close to the surface (upper 20 m) is often young water, meaning that it has been recharged not too long ago.  Because it is so close to the surface, it is vulnerable to contamination.   Deeper water is probably a bit older and because it is farther below the surface, it is more protected against surface contamination and the quality of this water is generally good.  Really deep groundwater (> 200 metres deep) will be even older and may have elevated salt content due to the long residence time of the water.

How much groundwater do we have?

Groundwater is a significant source of water, and in some parts of the country the only source of potable water.  According to the Department of Water Affairs and Sanitation, the most recent estimate of sustainable potential yield of groundwater resources at high assurance is 7 500 million m³/a, while current groundwater use is estimated at around 2 000 million m³/a. Allowing for an underestimation on groundwater use, about 3 500 million m³/a could be available for further development.  Unfortunately, if there is a shortage of water on one side of the country, it cannot be supplemented with water from the other side.
 
With a drought, the amount of water falling from the sky is below average, which means that the available water to recharge is also less. With less recharge water, the groundwater levels will decline.  To make things worse during a drought, groundwater users will pump more water to make up the deficit in rainfall, thereby accelerating the drop in water levels.

“Groundwater can be used to help humanity. The pore space in aquifers can be used to store water during a wet period, to be used later during a drought. This is called water banking, where water is injected into the aquifers (artificial recharge) during a period when there is enough water and pumped from the same aquifer during a period of water shortage,” says Dr Lukas. 

News Archive

Always good to be honoured at home, says Justice Richard Goldstone
2012-02-06

 

Justice Richard Goldstone received an honorary doctorate from the university on 3 February 2012.
Photo: Duard Grobbelaar

 

Dumela article (pdf document)
Justice Richard Goldstone's - acceptance speech (pdf document)
Mail & Guardian article (pdf document)

The University of the Free State (UFS) is determined to make a success of its academic and human projects, and is not prepared to compromise on standards in the process.

This was the message of Prof. Jonathan Jansen, Vice-Chancellor and Rector, at our universities official opening on Friday 3 February 2012. These projects, said Prof. Jansen, are the foundation of the institution.

The official opening coincided with an honorary doctorate in Law conferred on Justice Richard Goldstone.

The UFS has enrolled the “smartest and most diverse class since 1904,” Prof. Jansen said.
Top learners with six A’s, and more learners from top schools inside and outside South Africa, have made the UFS their university of choice. “We are determined that the best students must study at Kovsies.”

Prof. Jansen also referred to learners in the school system who sit and wait while teachers fight amongst themselves at the education departments. “What are we going to do with those students?” The UFS provides an opportunity for these students to enter higher education with its University Preparation Programme on its South Campus in Bloemfontein. “The fastest growth at our university is on this campus. It is set aside for children who cannot be taken up in the mainstream.”

Some of the students who were part of this programme are doctors, lawyers and teachers today.

“We set a high standard in our academic project to make sure our students are the best available.”

In its Schools Project, the UFS has 23 schools under its wing and the net is broadening. Pass rates in these schools improved dramatically; in some from 13% to 100% in one year.

The human project sets standards for good behaviour. “I was astounded to see how young people get together to find other people as human beings,” Jansen said. “I have enormous hope for this country.

Some of the other projects he mentioned were the provision of more space for students to study, a refocus on the Qwaqwa Campus in the Eastern Free State, the placement of new academics, and agreements with universities abroad on the placement of young scholars.

After receiving his honorary doctorate, Justice Goldstone congratulated the university on the fact that transformation did not lead to standards being compromised.

“The university now takes its place as a leading university on our continent. The leaders of the university can hold their heads up high about their achievements.”

Judge Goldstone, the bearer of 26 honorary doctorates from various countries around the world, said: “It is always good to be honored at home”.

The official opening was attended by staff, students, guests and community leaders.
 
 

Media Release
3 February 2012
Issued by: Lacea Loader
Director: Strategic Communication
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: news@ufs.ac.za
 

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