Population growth and the uncertain effects of climate change are likely to have significant financial, human and ecological impacts on the already scarce water supply in South Africa, says Talbot & Talbot laboratory director Vanessa Talbot.
According to a paper by Kathrin Knüppe, published in Water SA (online), the reduction in the volume of available subsurface water reserves, owing to the permanent increase in water demand, will represent a major environmental trend for the next 25 years.
South Africa’s groundwater resources supply about 15% of the water consumed, of which nearly 64% is used for irrigation in agriculture and mining, while domestic consumption constitutes 8%. More than 280 cities and towns are either wholly or partly dependent on ground- water in South Africa.
The Department of Water Affairs (DWA) has developed a groundwater protection strategy to ensure that groundwater is recognised, used and protected as an integral part of South Africa’s water resources. The strategy contains a series of groundwater quality management programmes, each with clearly defined objec- tives, action plans and timeframes.
Further, the department has published a series of guidelines, such as guidelines to protect groundwater from contamination.
“Although groundwater is a vital source of water and has given rise to several short- and medium- term socioeconomic benefits, the additional pressure has put many aquifers at risk, owing to high extraction rates. “The motivations behind the regulations and guidelines from the DWA for the management of groundwater resources have been difficult to account for and implement on a regional level and are subsequently largely overlooked or neglected,” says Talbot.
The protection of groundwater requires education, awareness, resource regulation and management, cooperation networks and stakeholder involvement to ensure it remains sustainable.
Identifying and quantifying groundwater pollution requires an aquifer-, site- and pollutant-specific approach, which requires a joint effort by hydrogeologists and pollution-monitoring experts.
Groundwater quality can be managed in an integrated and sus- tainable manner within the frame- work of the National Water Resource Strategy, thereby providing an adequate level of protection for groundwater resources and securing the supply of water that is of an acceptable quality.
In the Policy and Strategy for Groundwater Quality Management in South Africa (DWAF, 2000), the department describes the means and measures available to achieve groundwater quality management.
It stipulates the minimum requirements for water monitoring for industries and waste facilities; however, general pollution from anthropogenic sources is more difficult to monitor and control.
The increase in demand for water often results in the over- exploitation of aquifers, which, in turn, leads to the wells drying up. The consequences of overexploitation include lower groundwater tables, which result in a decoupling of the groundwater and surface-water system, including water exchange between rivers, wetlands and springs.
The saline water is common in coastal regions and often results in lowered groundwater levels and increased costs.
Talbot says the trend will be exacerbated by worldwide population growth, agricultural practices and landscape alterations, increases in urban populations, the demand for domestic and public drinking supplies, and industrial activities.