Major dams continue to maintain strong storage levels
The Department of Water and Sanitation's (DWS) latest weekly state of reservoirs report indicates that the Integrated Vaal River System (IVRS) remains in a strong and stable condition, despite minor week-on-week fluctuations in water levels across several major dams.
While some reservoirs recorded marginal declines due to routine operational releases, seasonal evaporation and reduced inflows, overall storage levels remain exceptionally healthy. This continues to provide confidence in the system's ability to meet domestic, industrial and agricultural water demands while safeguarding long-term water security.
The Vaal Dam, the country's second-largest dam and the primary water source for Gauteng and surrounding provinces, declined slightly from 103.4% last week to 102.4% this week. Despite the marginal decrease, the dam remains above full supply capacity, reflecting exceptionally healthy storage levels. During the reporting period, inflows of 47.79 m³/s exceeded controlled outflows of 16.865 m³/s, indicating that water continues to enter the reservoir while releases are carefully managed to regulate storage levels and maintain downstream river flows. With no rainfall recorded and 4 mm of evaporation observed during the week, the slight decline is consistent with normal seasonal conditions and does not pose any concern.
Grootdraai Dam recorded a marginal decline from 98.9% to 98.6%. The slight decrease reflects normal operational balancing between inflows, releases and water demand. Remaining close to full capacity, the dam continues to provide a reliable water supply to municipalities, industries and surrounding communities within its catchment.
In contrast, Bloemhof Dam recorded an increase from 105.0% to 106.71%, remaining well above full supply capacity. The dam registered a gauge plate reading of 18.340 metres with controlled releases of 10.633 m³/s. No rainfall was recorded during the reporting period, while 2 mm of evaporation was observed. The increase reflects the continued movement of water through the lower Vaal River system from upstream reservoirs and contributes positively to downstream water availability, irrigation requirements and effective river regulation.
Sterkfontein Dam, the strategic reserve of the Integrated Vaal River System, remained unchanged at 99.0%. Its stable storage level reflects balanced operating conditions and continues to provide an important buffer that strengthens long-term water security, particularly during periods of reduced rainfall or increased water demand.
Within the Lesotho Highlands Water Project (LHWP), Katse Dam declined from 88.2% to 86.8%. The decrease is attributed to ongoing operational releases and scheduled water transfers into South Africa. Although lower than several other reservoirs within the system, Katse Dam remains at a healthy storage level and continues to fulfil its transfer obligations while supporting the overall performance of the IVRS.
Similarly, Mohale Dam recorded a marginal decrease from 101.9% to 101.8%. Despite the slight decline, the reservoir remains above full supply capacity, indicating continued surplus storage. As an integral component of the Lesotho Highlands Water Project, Mohale Dam continues to support water transfers into the Integrated Vaal River System, reinforcing water security for South Africa's economic heartland.
Overall, the Integrated Vaal River System declined marginally from 99.2% last week to 98.9% this week. The slight decrease reflects the combined effects of routine operational releases, ongoing domestic, industrial and agricultural water consumption, seasonal evaporation and reduced inflows following earlier rainfall events. While several dams experienced minor declines, the increase at Bloemhof Dam helped maintain overall system stability.
An overall storage level of 98.9% confirms that the Integrated Vaal River System remains in an excellent state, with sufficient water available to meet current demand while preserving strategic reserves. The healthy storage levels underscore the resilience of the catchment following a favourable rainfall season and provide assurance that the system is well-positioned to sustain water supply in the months ahead.
The Department continues to closely monitor reservoir performance and manage water releases responsibly to balance water supply requirements, infrastructure safety and environmental flow obligations.
The Department of Water and Sanitation welcomes the continued healthy status of the country's major reservoirs and reminds all water users that, despite the favourable storage levels, South Africa remains a water-scarce country. Water conservation and the responsible use of water remain essential to protecting this valuable resource and ensuring sustainable water security for current and future generations.
For more information, contact:
Wisane Mavasa
Spokesperson for the Department of Water and Sanitation
Cell: 060 561 8935
E-mail: mavasaw@dws.gov.za
Maria Lebese
Gauteng DWS: Communication
Cell: 082 611 9264
E-mail: lebesem@dws.gov.za
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