Fewer gates opened at Vaal Dam despite rising levels, showing shift in flood response strategy

While the Vaal Dam has exceeded its full capacity, authorities have opted to open only five sluice gates—far fewer than during past flood events. This cautious approach reflects a more calculated and confident strategy in managing the country’s vital water infrastructure.

With the rainy season drawing to a close, officials say they are monitoring inflows closely and believe the dam’s level will stabilise without triggering emergency releases. Current reports show inflows at 1055.1 cubic metres per second, with controlled outflows of 813.4 cubic metres per second.

Improved response compared to past years

Midvaal councillor Pieter Swart noted that the Department of Water and Sanitation’s measured response marks a dramatic improvement from 2023, when the dam hit a similar level and 12 sluice gates were opened. “They seem more confident this year that inflows will decrease,” he said.

Swart believes this shift is due to better planning and a more accurate monitoring network. “The department can now see up to four days ahead, thanks to over 400 measuring stations in the system. That gives them a real edge,” he said.

Public less alarmed as understanding improves

In contrast to previous years, communities in the Vaal Triangle have reacted calmly to rising dam levels. Swart said most people he’s spoken to now understand that the dam doesn’t simply overflow but instead undergoes controlled releases.

“People are better informed now. They know that managing the Vaal’s capacity is essential to securing Gauteng’s water supply long-term,” he explained. “It’s no longer seen as an immediate danger.”

Evacuations remain limited to high-risk areas

This season has also seen fewer evacuations, with only the most vulnerable properties affected. “There hasn’t been a surge in evacuations in my area,” Swart said. “Only people whose homes are already in low-lying areas impacted by high water have had to leave.”

He confirmed there had been some evacuations downstream, including parts of Orkney and recreational areas like the Vaal River Boating Club, but said these were expected given their locations.

Controlled strategy praised for minimising risk

Swart credited the department’s earlier interventions for keeping flood risks low while maintaining critical water reserves. “Keeping five gates open while the dam is over 115% full shows they’ve got a firm handle on things this time,” he said.

By avoiding late reactions—as seen in 2023 when extreme flooding followed the opening of 12 gates—authorities have managed to protect both water infrastructure and nearby communities.

The Vaal Barrage system currently shows a level of 7.4 metres, outflow at 1093.0 cubic metres per second, and water temperatures at 19.2°C, suggesting the system is being handled with care as the country exits its peak rainfall period.

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