Groundwater: hidden but never forgotten

Fanus Fourie (FF) National Chairperson, GWD Yazeed van Wyk (YW) National Treasurer, GWD

How much groundwater is used in South Africa? FF Between 13% and 16% of the nation's total water supply originates from groundwater. However, this would exclude all boreholes that are not registered at the Department of Water and Sanitation.

YW In some areas, groundwater provides up to 100% of the water supply.

How much local data is available on groundwater? FF The DWS monitors approximately 1 800 boreholes around the country and has issued in the order of 25 000 wateruse licences. As a borehole user, it is Part of the Geological Society of South Africa (GSSA), the Ground Water Division (GWD) is a body of scientists and technicians who have an interest in the optimal development of South Africa’s groundwater as a limited natural resource.

important to monitor your own borehole water quality and levels.

YW The Water Research Commission developed a study called the Strategic Water Source Areas (SWSA) of South Africa, showing that 50% of the water comes from just 10% of the land area.

There are 57 SWSA-gw (groundwater) – about 11% of South Africa’s total water – with 37 of these being nationally strategic. The SWSA-gw supply 32% of the settlements that get more than half of their supply from groundwater (and house 4% of the national population). They supply 44% of the groundwater for agriculture, and 32% of the groundwater used for industrial purposes in South Africa. Groundwater is also the main source of water for a further 268 settlements in South Africa. This is significant.

Is groundwater an underutilised resource? FF Yes and no.

Yes, because 7.5 billion m3 per annum of groundwater is available and there is 10 billion m3 per annum of surface water, but almost all of the surface water is fully allocated. Around 19% of all groundwater is found in KwaZuluNatal, but most of the province’s water is sourced from a river or a dam. Groundwater is definitely underutilised in KwaZulu-Natal.

South Africa is currently using around 50% of available groundwater and still can develop the other 50%. But if a community has a river, it will not go to the expense of drilling a borehole to utilise available groundwater. There is around 2 billion m3 per annum of groundwater that can be developed.

On the other hand, groundwater is not underutilised. In fact, it is overutilised in places like the Karoo.

Groundwater has massive potential. Cape Town will be pumping roughly 10 Mℓ/day of groundwater. Once Port Elizabeth’s groundwater scheme is in place, roughly 15% to 20% of all its water will come from groundwater. Groundwater in Brandvlei in the Karoo is pumped as far as 50 km from the town. Many towns and communities are supplied solely from groundwater.

In certain cases, we can utilise more groundwater; in other cases, we need to focus on protecting our groundwater.

Groundwater protection zoning is aimed at safeguarding the quantity and quality of groundwater. A community cannot live on top of a wellfield. Petrol stations or ventilated improved pit latrines should not be close to a borehole. In some cases, development needs to be reconsidered if groundwater earmarked by the municipality for community use will be impacted if the development goes ahead.

YW Typically, we find groundwater in abundance where we don’t need it; and where we need groundwater, we don’t have it. This is due to the complexity of the geology, hydrogeology and variability in rainfall.

With water security as a priority, why is groundwater underutilised? YW The development and management of groundwater does not reflect its importance. The development of the resource is left at the mercy of municipal procurement and poor operations and maintenance. Groundwater, unlike surface water, requires constant monitoring and maintenance of the infrastructure. A lack of groundwater resources is often blamed for service delivery issues when poor development, operations and maintenance are the root causes.

Groundwater is underutilised owing to the following: • high cost and complexity of assessment – the myth that groundwater is where you want it to be and it is clean and cheap needs to be scrapped from our textbooks • dispersive resource makes for high monitoring costs – we need to see it as high-capital items in our spheres of implementation • resource invisibility and time lags of observing resource impacts • highly variable aquifer vulnerability to contamination • near irreversibility of aquifer contamination.

What needs to be done to further develop groundwater? FF Municipalities and private individuals need to follow the correct procedures when exploring for groundwater. It needs to be done in a professional manner and it is important to use a registered professional. The GWD has a large database of registered professional hydrogeologists that can assist (visit https://gwd.org.za for the database). Also, an uncertified driller may damage or destroy an aquifer. I have seen cases where the borehole was not sealed off properly; it started to leak, and pollution entered the aquifer. And then it is not available for anyone to utilise. A professional will also establish how much should be pumped out of the borehole and for how long, because if it is over- or under-pumped, the aquifer can be damaged.

YW There needs to be an exploration and assessment programme (hydrocensus, geological review, geodynamics, strain analysis). One should never target a potential site blindly with a drilling rig. We need a mindset shift that sees groundwater not as an emergency water supply but a long-term, sustainable solution to water security issues.

How can we better manage groundwater? FF Groundwater management seeks to balance and mitigate the detrimental impacts of the development and operation of groundwater. There are a number of elements to consider: • Protect the wellfield: If people are living on top of your aquifer, there is a high likelihood that it may be polluted.

The wellfield needs to be fenced off. But for maintenance and daily operations, there must be easy access to the borehole. • Planning: There may be a possibility that one requires more water from the borehole than can be extracted. It may take two to four years to get another groundwater scheme up and running. • Maintenance: Often, when a borehole is not working, it is because a pipe broke, or there is a power issue, a stolen cable, or faulty pump or tap. • Daily operations: Water levels need to be measured daily. If no one knows how much water has been extracted, and how much the aquifer has been replenished, the borehole may dry out. • Groundwater education: The community using the borehole water needs to understand where the water is coming from, how much water can be used, and how to avoid polluting the aquifer. The GWD is available to provide help and technical advice.

GROUND WATER DIVISION (GWD)

• Established in 1978 • Essentially a non-profit association, it is committed to upholding and promoting professionalism in the field of groundwater among its membership • The GWD is a community of professionals who help South Africans understand and manage groundwater • The 17th biennial Groundwater

Conference will be held between 17 and 20 October as a hybrid event, broadcasting from Gauteng • The GWD focuses on networking, knowledge transfer as well as capacity and awareness building through initiatives such as conferences, seminars and courses, talks and media relations, publications and sponsorships • It has a large database of registered professional hydrogeologists

For more information, visit the GWD website https://gwd.org.za