DWS Maintains Vigilant Oversight of Vaal River Dams to Mitigate Flood Risks

In its latest update issued on Tuesday, DWS confirmed that two sluice gates remain open at the Vaal Dam to maintain a controlled water outflow of 292.86 cubic metres per second (m³/s).

As the Upper Vaal Catchment braces for continued rainfall, the Department of Water and Sanitation (DWS) has reaffirmed its unwavering commitment to ensuring the safety and functionality of the Integrated Vaal River System (IVRS). With elevated inflow levels across key dams, the department is taking proactive steps to manage water volumes and safeguard surrounding communities, infrastructure, and ecological systems.

Strategic Water Release Management at Vaal Dam

In its latest update issued on Tuesday, DWS confirmed that two sluice gates remain open at the Vaal Dam to maintain a controlled water outflow of 292.86 cubic metres per second (m³/s). This decision follows the recent closure of the third sluice gate on 16 April 2025, as part of the department’s adaptive water management protocol.

Although water inflow at the Vaal Dam has seen a decline — from 277.63 m³/s to 229.71 m³/s — dam storage levels remain high, currently sitting at 107.69%, exceeding the dam’s full supply capacity. These levels necessitate precise operational responses to prevent uncontrolled overflows and mitigate downstream flooding risks.

Bloemhof Dam Releases Scaled Back for Safety

The Bloemhof Dam, another critical component of the IVRS, has also experienced elevated water levels. To address this, controlled water releases were gradually scaled back from 700.0 m³/s on 15 April 2025 to 500.0 m³/s on 18 April 2025. The current storage level at Bloemhof stands at 106.91%, indicating an ongoing need for vigilant management and responsive water discharge.

Such reductions are implemented to align with downstream absorption capacity and maintain structural integrity at the dam site. The department emphasized that these releases are essential for the safe operation of the dam and must be conducted in a regulated manner to protect human settlements and agricultural activities along the river basin.

Grootdraai Dam Gates Closed as Levels Stabilize

At the Grootdraai Dam, all sluice gates have now been closed as the situation stabilizes. Storage capacity here is recorded at 104.90%, with inflows reported at 41.43 m³/s. While the dam remains above its full supply level, the moderated inflow presents a less urgent threat, allowing the department to temporarily cease releases while continuing to monitor conditions.

Upholding Dam Safety Standards and Risk Mitigation

DWS reiterated that the core principle behind opening sluice gates lies in controlled water discharges. This is particularly crucial when dams exceed their designated storage thresholds. These preventive actions are designed to protect the structural integrity of the water resource infrastructure and prevent catastrophic outcomes, including dam failures that could result in extensive flooding, displacement, and loss of life.

By adhering strictly to dam safety protocols and hydrological monitoring, the department ensures that each release is informed by real-time data and comprehensive flood risk assessments.

Preparedness and Public Assurance

“The department will continue to monitor inflow water levels in the Integrated Vaal River System to ensure that the necessary precautions are in place,” DWS stated. “All actions are aligned with dam safety standards and modern hydrological monitoring systems to safeguard infrastructure and attenuate any flood conditions.”

DWS’s efforts not only highlight the importance of robust water resource management systems but also demonstrate a commitment to transparency, environmental stewardship, and public safety during periods of hydrological uncertainty.

As rainfall patterns continue to shift under the influence of climate variability, strategic dam operations such as those currently underway are set to become more frequent and crucial. Stakeholders and communities are encouraged to stay informed through official channels and adhere to safety advisories issued by local authorities.