DWS to Keep Vaal Dam at Full Capacity Ahead of Predicted Below-Normal Rainfall

In its latest weekly assessment, the DWS reported the Vaal Dam’s water level at 106.3% capacity, a slight drop from 106.5% the previous week.

In a proactive step to safeguard water security, the Department of Water and Sanitation (DWS) has announced plans to maintain the Vaal Dam at full capacity until the onset of the summer rainy season. The move comes amid South African Weather Services (SAWS) forecasts predicting normal to below-normal rainfall for much of the country’s central interior, which includes key economic and population centres.

While above-normal rainfall is expected in the southwestern and coastal regions, the department is prioritising water storage in strategic reservoirs such as the Vaal and Bloemhof Dams to cushion communities and industries from potential drought impacts.

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Current Status of the Vaal Dam

In its latest weekly assessment, the DWS reported the Vaal Dam’s water level at 106.3% capacity, a slight drop from 106.5% the previous week. The dam is currently storing approximately 2.57 billion cubic metres of water, well above its designated full supply volume.

This surplus, the department explained, is the result of above-average rainfall earlier in the year combined with effective water resource management during the low-flow season. Despite the gradual decline caused by usage and natural evaporation, storage levels remain exceptionally high.

“The Vaal Dam, as a core component of the Integrated Vaal River System (IVRS), is critical to ensuring reliable water supply to Gauteng and the Free State,” the DWS said, adding that keeping the dam full is part of a broader strategic water management framework designed to preserve resilience during dry periods.

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Performance of the Integrated Vaal River System

The IVRS is currently operating at 101.0% capacity, only slightly lower than last week’s 101.2%. The system’s stability is bolstered by multiple reservoirs that remain at or near full supply:

• Grootdraai Dam: steady at 99.4% for the past week

• Sterkfontein Dam: down marginally from 99.4% to 99.3%

• Bloemhof Dam: increased from 108.8% to 109.2%, well above last year’s level of 91%

The Bloemhof Dam, which has been releasing water steadily since May when normal operations resumed, will continue to be kept above 100% full supply capacity and undergo constant monitoring to ensure optimal performance.

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Lesotho Highlands Water Project Contributions

Beyond South Africa’s borders, the Lesotho Highlands Water Project remains a critical feeder into the IVRS. Its dams showed mixed trends:

• Katse Dam: decreased from 91.5% to 90.6%

• Mohale Dam: minor dip from 102.2% to 101.2%

Despite the small declines, the cross-border scheme remains stable and continues to support South Africa’s water security strategy.

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Preparing for Climate Variability

The DWS stressed that keeping the Vaal Dam and other IVRS reservoirs full is a deliberate climate resilience measure, ensuring a buffer against erratic rainfall patterns and rising water demand in urban centres.

“Efficient water use remains vital in sustaining long-term water security amid the increasing pressures of climate change and urban demand,” the department said, urging citizens to continue using water responsibly despite current abundance.

With Gauteng and surrounding provinces heavily reliant on the Vaal River System, maintaining high storage levels is seen as an essential safeguard, ensuring that municipal, industrial, and agricultural users have access to reliable water supplies well into the dry season.