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Vaal Dam. Picture: Vaal Weekblad
The Department of Water and Sanitation (DWS) is monitoring the Vaal Dam closely as its water levels have risen to 101.13% on Monday, 10 March, following a period of heavy rains.
These hydrological monitoring systems are in place to maintain the integrity of the water resource infrastructure, as well as reduce flood conditions while keeping the dam at full capacity, according to DWS spokesperson Wisane Mavasa.
Mavasa told The Citizen that the dam — near Vereeniging on the border of the Free State, Gauteng and Mpumalanga provinces — has an additional 26% absorption capacity.
“We will provide another update this week, but as part of our flood management plan to ensure that there is balance between the inflows and outflows at the dam, the department is currently releasing at 61.2 cubic metres per second (mᵌ/s) using five valves at the dam.
These releases are meant to ensure that the dam’s capacity stays within the range of 100% to 103% at the current inflow levels.
The Vaal Dam has eight valves in total that are used for river releases. On normal day-to-day releases, using two valves range from 16.8 mᵌ/s to 17.6 mᵌ/s in order to keep the natural flow in the river.
On Friday, the dam’s water levels reached 100% for the first time since 2023.
The current water levels represent a remarkable recovery compared to earlier this year, when the dam’s capacity plummeted to below 30%.
Midvaal councillor, Pieter Swart, has been providing regular updates on the state of the Vaal Dam on Facebook. Take a look.
Following the recent torrential rain, Minister of Water and Sanitation, Pemmy Majodina, reassured the public that the dam’s sluice gates are functioning properly.
Majodina said communities would be informed before any release, urging calm as the dam level increased rapidly over the past few weeks.
“We cannot allow the dam to overflow and risk disaster. Our safety checks confirm the dam is stable, and any release will be strategic to maintain normal levels,” Majodina said.
There are currently no sluice gates open at the Vaal Dam or Bloemhof Dam, which is sitting at 100.94%
The Bloemhof Dam is located downstream of the Vaal River catchment and has an additional 16% flood absorption capacity.
Due to increased river inflows from the upper catchments and recent rainfall in the Bloemhof catchment area, controlled outflow releases have also been activated at the dam and are water is currently released at 320 mᵌ/s through outlet pipes.
These releases are meant to facilitate the proper management of water levels and to keep the dam at or below its full supply capacity of 100%.
The department also notes that along the Vaal River and downstream the Vaal Dam, water levels may rise as a result of inflows from Suikerboschrand, Klip and Rietspruit tributaries over the high flow period due to torrential rains in the catchments of these rivers.
The heavy rainfall in most parts of the country has necessitated the department to implement dam releases according to its safety protocols in all its major dams to prevent dam failures and major disasters in the country.
As part of the flood management plan, dam safety protocols are activated when dams breach the full capacity mark and overflow to prevent the infrastructure from failing which may lead to a dam bursting and causing a disaster of unimaginable magnitude and also leave the areas it supplies without sources of water.
Water expert Carin Bosman addressed concerns about the potential overflow risks of the Vaal Dam.
“The dam is designed to overflow, so there is no risk associated with the overflow,” Bosman previously told The Citizen.
According to her, overflow events typically occur “towards the middle end of March, beginning of April, and that’s the dams designed to handle overflow”.
Despite the positive news, there have been concerns about potential overflow risks.
However, officials have clarified that such worries are largely unfounded due to the dam’s design.
“The Vaal Dam doesn’t ‘overflow’ in the way some other dams will do. It makes use of sluice gates to release water in a controlled manner, once the dam reaches 100%.” Swart explained.
Water expert Carin Bosman reinforced this point, emphasising that the concept of “overflow risk” is technically misplaced.
“The dam is designed to overflow, so there is no risk associated with the overflow. The risk of overflow is not a risk. The dam is designed to overflow,” Bosman stated.
Bosman had previously told The Citizen that overflow events typically occur “towards the middle end of March, beginning of April, and that’s the dams designed to handle overflow.”
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