Above-normal rainfall has seen the Vaal Dam, which supplies most of Gauteng with water, fill up to 108.5% by Monday morning after reaching the 110% mark in early January.
However, the level decreased, and on January 12 dropped to 103.5%.
Department of Water and Sanitation spokesperson Sputnik Ratau said this year’s dam levels were thriving when compared to previous years.
“Compared to other years, the current levels are much better. Last year at this time the national average was 72.2% and right now it is at 92.3%.
“The biggest water supply system, the Integrated Vaal River System, was at 74.1% and currently it is at 98.4%,” said Ratau.
Dam levels were high because of La Niña, with South Africa set to receive above-normal rain throughout the summer season, meteorologists predicted.
La Niña is an intermittent climate phenomenon caused by the cooling of surface ocean water along the tropical west coast of South America.
According to the South African Weather Service, La Niña conditions are expected to continue during the summer, and the predictions for rainfall over the larger part of the country are for enhanced probabilities of above-normal rainfall during the January, February, March, April and May months.
The department said it had opened five sluice gates to control and manage inflows.
Two sluice gates were opened on Monday, while another gate was to be opened yesterday morning.
“The department took a decision to keep four gates open for now, with the possibility of more releases happening in the very near future,” Ratau said.
Despite there being advantages to the level of the Vaal Dam being over 100%, there are also disadvantages to it.
“The benefits relate to the security of water availability that must be married to responsible water use,” said Ratau. “The disadvantage could be the impact on the infrastructure itself. This is why the department’s safety and hydrology units become very important,” he said.
Also, when the sluice gates were opened the outflow could negatively affect those living near the dams.
Huge increases were expected into the system over the next few days.
“At the moment, indications are more towards continuing increases. We are continuing to monitor all systems, with a particular eye on the Vaal-Orange River System where there is a lot of activity,” he said.
Ratau warned downstream communities to be cautious and observe basic safety measures.
“Farmers are asked to remove equipment that may be damaged due to the outflow. This is also a warning for communities to ensure that children do not swim near the stream.
“It is always most important to protect and save lives and livelihoods. The department will continue to monitor the volumes, but the sluice gates will remain open until further notice,” said Ratau.
Despite the recent heavy rainfall, South Africa remained a water-scarce country and the department reiterated the importance of using water sparingly through its social media pages regularly.
“It is important to use water sparingly. We are a semi-arid country, so every drop counts,” he said.