Vaal Dam Water Levels Exceed 107%, Third Sluice Gate Opened to Manage Inflows

The third sluice gate was opened on Tuesday afternoon and is expected to boost the dam's water releases to approximately 400 cubic metres per second (m³/s).

In response to rapidly rising water levels caused by ongoing rainfall, the Department of Water and Sanitation (DWS) has opened a third sluice gate at the Vaal Dam to increase outflows and reduce pressure on the dam infrastructure. As of the latest readings, the Vaal Dam is sitting at 107.30% of its capacity—well above the full supply threshold—prompting urgent yet controlled water management interventions.

The third sluice gate was opened on Tuesday afternoon and is expected to boost the dam's water releases to approximately 400 cubic metres per second (m³/s). This measure is designed to mitigate the increased inflows from upstream sources and forms part of the department’s proactive approach to dam safety and flood risk management.

Safety Assurances and Downstream Impacts

Despite the increased outflow, the DWS has reassured communities downstream that the current rate of water release remains within safe operational limits. There is no immediate threat of overtopping or flooding of riverbanks downstream of the Vaal Dam.

"These releases are being carefully managed to ensure safety along the Vaal River system. All operations remain within our standard flood attenuation protocols," the department confirmed in an official statement.

Upstream and Downstream Coordination

Grootdraai Dam, situated in Mpumalanga within the Upper Vaal River Catchment area and upstream from Vaal Dam, has also seen a rise in water levels. Currently at 103.37% capacity, the dam had its sluice gate opened by one metre, which has now been increased to 1.5 metres to release more water downstream and balance the system.

Meanwhile, Bloemhof Dam, located further downstream, has temporarily halted its outflows on Tuesday due to essential maintenance work. The department stated that water releases from Bloemhof would resume in a staggered manner once the maintenance is complete, minimizing the potential for wave-action flooding.

“As soon as the maintenance work at Bloemhof is concluded today, the staggered release of water will begin to ensure smooth flow and prevent any sudden rise in downstream water levels,” the department added.

The current water level at Bloemhof Dam stands at 96.65%. According to hydrological forecasts, increased outflows from Vaal Dam are expected to reach Bloemhof within three to four days, likely contributing to a noticeable rise in water levels there. If necessary, the department says it will gradually adjust outflows from Bloemhof to maintain safe conditions.

Background and Future Monitoring

This latest intervention follows the opening of the second sluice gate at the Vaal Dam on Friday, 28 March, as part of a phased response to increasing inflows.

The DWS continues to closely monitor the entire Vaal River System, which includes a network of interlinked dams and catchment areas that are vital to water supply, agriculture, and hydroelectric operations across several provinces.

“These pre-emptive water releases are part of our dam safety protocols to protect both infrastructure and the surrounding communities. It is essential that we retain the ability to absorb further rainfall and inflows, especially as the rainy season comes to a close,” the department emphasized.

Residents and businesses located downstream of the affected dams are encouraged to stay updated through official DWS channels and to exercise caution near rivers and low-lying areas over the coming days.

Conclusion

The Department of Water and Sanitation remains on high alert and is working in coordination with local disaster management teams to respond swiftly to any developing risks. The controlled water releases are aimed not only at preventing flooding but also ensuring that dams can continue to serve their critical function as water reservoirs and flood management infrastructure throughout the year.