South Africa’s groundwater, on which the country greatly depends for domestic usage, needs to be used wisely.
This is the clarion call made by Dr Eelco Lukas, a geohydrologist and the director of the Institute for Groundwater Studies at the University of the Free State (UFS).
South Africa is a water-stressed country with low rainfall. Lukas said that nearly two thirds of the country depends solely or partially on 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,” he stated.
“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.”
Lukas said according to findings, numerous towns and communities depend solely on groundwater and many towns use a combined supply of surface water and groundwater.
“When the town or settlement is far from any surface water and groundwater is available, boreholes are drilled.
“Most of the big cities use surface water in their water pipes. Almost all big cities worldwide are located close to a supply of fresh water.”
According to Lukas, the City of Cape Town has however drilled many boreholes in the past two years to augment water supply.
“Problems can arise when a borehole is drilled for a community with a certain number of people and soon there are many more people than the borehole can supply. It is not so much a case of the “borehole drying up”, but that the capacity was exceeded.”
With 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 from a milkshake. When five other people drink with straws from the same one, all will be left thirsty.
“Sustainable groundwater usage is the certainty that enough groundwater is available in years to come. Sustainability is dependent on two external factors: 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.”
Lukas said according to findings made by the Department of Water Affairs and Sanitation, a part of this resource is still available for 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.