Making SA’s groundwater last

Maintaining and managing SA’s scarce water resources have become highly contentious issues, especially in rural areas, says Gert Nel, partner and principal geohydrologist in SRK Consulting, East London.

It is imperative that water users and water service providers in South Africa start talking to each other to better manage scarce groundwater resources and avoid pumping our aquifers dry. Some towns in relatively dry provinces are increasingly relying on groundwater, in the absence of sufficient surface water in rivers and dams. In the Eastern Cape, for example, feasibility studies were carried out 12 years ago to establish the quantity and quality of groundwater, and a number of well-fields and boreholes were developed.

The issue now is to look after them. South Africa is blessed with substantial but finite groundwater resources. If we do not properly monitor and manage the boreholes we install, groundwater resources could easily be over-exploited and run dry. The entire costly process of finding other groundwater resources and accessing them will have to be repeated.

At the same time, it should be remembered that these resources are by no means limitless. It is vital, therefore, that water service providers (usually local municipalities) and private users (such as farmers) know how much water is in the aquifers they exploit, and how much off-take the aquifers can sustain.

At SRK Consulting, we have aimed, over several years, to convince the authorities to fund the establishment of groundwater models as part of aquifer management. A groundwater model is a scientific assessment of how much water is available, how much is replenished through rainfall and other sources such as rivers, and how much can actually be abstracted before the sustainability of the aquifer is threatened.

This has proved to be a good starting point for water-planning strategies, although it does not, of course, solve the problem of monitoring and management. Local authorities, for example, have generally only looked at their own water use – that is, in the homes and businesses supplied under the jurisdiction of towns and villages – when checking their abstraction levels against the flow potential of the aquifer.

The ‘private use’ of groundwater – mainly by farming communities – is often not included in the calculation because farms are usually not supplied by local authorities. Yet our experience at SRK Consulting has shown that private abstraction for irrigation often makes up a significant portion of water pumped from an aquifer.

So, when asked by water authorities to recommend how much water they can pump for their needs, we might conclude that there is enough potential in an aquifer for the town. But if we add the demand from, for example, the farming community close by, we realise that the aquifer could run dry within a few years. This situation demands greater co-operation between the municipalities and the agricultural sector, an area of some sensitivity, as many farmers have in the past generally been left to operate on their own in this regard.

What the law states
The law is clear that groundwater is a public asset – it does not belong to the person on whose land it occurs. So private users cannot use as much as they want, or as much as they can pump from their boreholes. That is why the law requires private users to authorise their water abstraction with the Department of Water Affairs.

Co-operation
As one of those provinces with insufficient surface water, the Eastern Cape is growing more dependent on groundwater, with many municipalities looking to develop more production boreholes on private properties – another reason for a need for greater co-operation between these parties.The challenge is to get the authorities and private users around a table to explain the need for better groundwater management, as in many cases they are both pumping from the same aquifers. The danger is that, without sufficient co-operation, the resources will be depleted, leaving both parties without sufficient water.

This is not a significant issue in areas where government is the main landowner (for example, communal land), but it could prove problematic where towns are dependent on groundwater, and farmers in the area have historically used groundwater for irrigation needs. Some Karoo towns are already facing these challenges; abstraction levels have grown substantially over time and the towns could face the depletion of their current water source within the next few years.

The Department of Water Affairs, as the overall custodian of the country’s water resources, is legally empowered to authorise water use, a process to which it applies certain terms and conditions. However, before it does authorise water use, it would have to take other abstractions in the area into account.
The problem is that many private users do not apply for these authorisations, so the department may not be fully aware of how much water is being drawn from any specific area.

When the municipality applies for water use authorisation in the same area, it is very likely that this will be granted, as the department will assume from its records that there is limited abstraction by private users in the area. The department is working on getting all large private users to authorise their boreholes and pumping levels.

If there is large-scale private abstraction in an area where the municipality also needs groundwater, there is always the danger of depletion. And when a municipality runs out of water, the first place they turn to is the Department of Water Affairs – and it often becomes the department’s problem. Implementing a groundwater model as part of a groundwater management strategy, and ongoing monitoring, would help avoid this situation.

The buck stops with the municipality
Lack of skills and financial capacity at local level is part of the problem. As the water service provider, the local municipality has traditionally not focused on the protection of aquifers because this requires extra funding and certain scientific skills for monitoring and management.

The local authority tends to prioritise the mandate of delivering water of sufficient quality to its customers, but in fact, it is also responsible for managing the local sources of water, not just the provision of water to the community. The Department of Water Affairs aims to protect water resources on a regional scale, and is not going to manage the municipalities’ water sources for them. – Tshidi Nkokou

Gert Nel is partner and principal hydrogeologist at SRK Consulting in East London. Email him at [email protected].

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