Now’s the time to go to ground over our water crisis
WATER scarcity, droughts and concerns over potable water are frequent in the mass media. In the shadows of the concerns in the news, social media are abuzz with finger-pointing on the reasons of water scarcity in the country.
In many instances, the issues can be solved by water professionals, provided we can get past the general misconception that South Africa has no water. Yes, the country is water-scarce, and, yes, water needs to be moved vast distances for supply, most notably to the urban areas. But in many areas, groundwater is a vastly underrated source of water, which can ameliorate ever-growing demands.
Tshwane has been supplied by the springs at the Fountains Valley since the founding of the city to this day. Situated in the Groenkloof Nature Reserve, the springs are protected against pollution and the water quality remains pristine.
Cape Town is known for a vast number of springs around Table Mountain which historically have supplied parts of the city. One such spring is at Oranjezicht, although it is no longer in use.
A number of boreholes contribute to water supply in Polokwane. Many smaller towns in the Karoo rely on this important resource, together with villages throughout Limpopo, the North West, the Free State and the Northern Cape.
Whereas dam levels reflect the imminent threat of droughts and climate change, the effect on groundwater is less obvious. We rely on regional monitoring networks of boreholes and models to anticipate the long-term behaviour of aquifers. This hidden nature is easily misinterpreted, leading to assumptions that groundwater is privately owned or completely resilient to climate change.
Ownership of groundwater is not private; its use is licensed and it’s a shared resource for all South Africans.
Properly qualified, professional geohydrologists or hydrogeologists are responsible for the characterisa- tion of subsurface waters. In terms of the quantity of water, knowledge is applied to studying the movement of water and the design of water supply schemes. Regarding the quality, one considers whether the water can be used without adverse effects to people or the environment.
Groundwater scientists have the knowledge and skill to address groundwater as a source for water supply in specific areas. Knowledge about geology teaches us about the water-bearing properties of rocks, and when sufficiently high, we term these aquifers.
Our understanding of fluid mechanics and chemistry allows us to determine flow rates, the composition of water and rates at which it can be pumped to supply water without damaging the aquifer.
Groundwater use is not merely a matter of acquiring a drill rig and drilling a borehole. The groundwater specialist relies on a holistic scientific approach of pre-identifying suitable targets.
Existing regional knowledge on boreholes, mapped geology and other physical measurements and models contribute to the understanding of the aquifer to increase the success.
For a successful borehole, finding water is not enough. A certain yield has to be guaranteed for sustainable pumping over prolonged periods of time.
This is not a straightforward task, and, especially in times of drought, an aquifer can be stressed.
During the current water scarcity, the Ground Water Division encourages the following:
Use groundwater as sparingly as you would any other source of water.
Groundwater at one locality inevitably influences water in rivers and aquifers elsewhere. One cannot see the water cycle as independent. Rainwater, groundwater and surface water all occur interdependently.
Groundwater recharge (implying the effect of rainfall on the groundwater levels) is not immediately linked to rainfall events. We require a substantial amount of continuous rainfall to raise the groundwater levels in the next seasons or even years.
Do not expect that a little rainfall on one day solves the water supply problem.
We are facing a drought and climate-change issues. It is not certain when, or even if, we will ever return to our “normal” rainfall pattern. Only climatologists and meteorologists can answer this question.
However, we should plan for a period of water scarcity exceeding this year.
If you are drilling a borehole, note that you are sharing an aquifer with others. You are not only pumping a borehole, but a shared resource that requires you to consider sustainable use.
For more water-saving tips, see the Department of Water and Sanitation’s homepage at https:// www. dw a . g ov. z a / e ve n t s / wat e r - week/2012/Tips.aspx.
Now is not the time to shy away from using groundwater, but rather to emphasise that we can tap into this resource provided we use the very special skill set of the country’s highly competent hydrogeologists and geohydrologists.
Groundwater is more abundant than surface water – undoubtedly so – but, as with surface water, its occurrence and quality are highly variable.
Specialist input is required and, as the groundwater professionals of the country, we urge all to abide by the water act and ensure that this resource is used sustainably.
This piece was collectively written by the Ground Water Division of the Geological Society of South Africa.