Vaal Dam level rises, but no need to open more sluice gates just yet

The Vaal Dam’s water level has risen to 115.57% capacity, but authorities are maintaining just five open sluice gates, signalling improved management compared to previous flooding events.

According to Thursday’s reports from The Reservoir, the dam’s inflow measured 1055.1m³/s while outflow remained controlled at 813.4m³/s.

Midvaal councillor Pieter Swart told The Citizen that this approach represents a significant improvement over past water management efforts.

“In 2023, when the dam was at 115%, 12 sluices were opened,” Swart explained.

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“Being at the end of the rainy season, the department must be confident that we won’t get any more large volumes of water entering the dam and that we will see a slow decrease in level from here on out.”

Vaal Triangle community understanding

Despite rising water levels, local residents appear to have a better understanding of the situation than in previous years, when similar conditions caused panic.

“The majority that I have spoken to understand the need for the management strategies and how important a full Vaal Dam is to Gauteng,” said Swart.

“Water is the most important resource we have and we have to prioritise its sustainable supply.”

He noted that most people now recognise the distinction between strategic water releases and actual dam overflow.

“The majority of people understand that ‘overflow’ is not really what the Vaal Dam does. The strategic release of water downstream is what some residents mean when they say the dam is overflowing,” Swart clarified.

ALSO READ: Vaal Dam flooding: Why residents are shrugging off evacuation warnings

Limited evacuations

Unlike previous flooding events, evacuations have remained minimal and targeted only the most vulnerable properties.

“From my view, I have not seen an increase in evacuation other than those that really had to; for example, their property might be in water at 105% already,” Swart said.

He mentioned that while he was unaware of designated evacuation locations in Midvaal specifically, there have been evacuations in other areas along the river system.

“I have not been informed of any evacuations in my ward in the Midvaal municipality. There have been evacuations in the Orkney area, though, Vaal River Boating Club, for example,” he added.

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Improved water release management approach

The Department of Water and Sanitation’s current approach represents a significant improvement over previous water management efforts, according to Swart.

Its extensive monitoring network allows for better planning and more measured responses.

“The Vaal Dam measuring stations, over 400 in total, can tell DWS 4 days in advance of the inflows before it reaches the dam wall,” Swart explained.

“With them keeping only 5 gates open, amidst the level rising to 115%, suggests that they have seen a decrease in inflows.”

This strategic approach has minimised downstream flooding while maintaining necessary water reserves.

“From my point of view, DWS had managed the level and flows very well this time around,” said Swart.

“In 2023, they may have left it too late and had to open 12 sluices to manage the level, causing extreme flooding downstream.”

The current situation at the Vaal Barrage shows a level of 7.4m with outflow at 1093.0m³/s and water temperature at 19.2°C, indicating a controlled management of the entire system as South Africa moves past the peak of its rainy season.

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