The Department of Water and Sanitation (DWS) reports continued high storage levels across the Gauteng water supply system, with several dams operating above 100% capacity, according to the latest weekly State of Reservoirs report.

This reflects sustained inflows following recent rainfall, supported by ongoing system management interventions such as controlled water releases to safeguard infrastructure and regulate downstream flows.

The Vaal Dam has increased from 104.7% to 106.5%, maintaining its status as a critically full reservoir operating above capacity. Current hydrological data indicate a water level of 23.030 metres, with inflows of 395.36 m³/s, significantly exceeding outflows of 119.590 m³/s, resulting in a net gain in storage. Rainfall of 20.4 mm was recorded, suggesting relatively stable weather conditions.

As part of proactive dam safety management, one sluice gate was opened yesterday at 10:00 and is scheduled to remain open for 24 hours to regulate water levels and prevent structural strain.

Levels above 100% indicate excess storage, requiring controlled releases to maintain safe operating thresholds while supporting downstream river systems.

Grootdraai Dam has recorded a slight decrease from 101.9% to 101.6% but remains above full capacity.

This marginal decline indicates that regulated outflows are slightly exceeding inflows, necessitating a stabilisation intervention to address water levels following recent high rainfall.

Despite this decrease, the dam continues to contribute positively to regional water supply security.

Sterkfontein Dam, a key strategic reserve, declined marginally from 99.8% to 99.7%. This minimal change reflects limited utilisation, preserving the dam’s role as a long-term buffer against potential supply constraints.

Its stability underscores its importance in ensuring sustained water security. Bloemhof Dam showed a notable increase from 110.0% to 111.9%, indicating substantial inflows and accumulation beyond its full supply capacity.

These elevated levels highlight strong upstream contributions and require careful management to mitigate potential flood risks downstream through controlled releases.

The Integrated Vaal River System (IVRS) has increased slightly from 102.4% to 102.6%, confirming that the system remains well above full capacity. This composite indicator reflects the performance of interconnected dams and transfer schemes, including contributions from the Lesotho Highlands Water Project.

Levels exceeding 100% indicate that the system is not only meeting demand but also maintaining surplus storage, providing a strong buffer against short-term supply risks.

However, it also reflects a highly regulated hydrological environment, where dam safety, flood control, and downstream requirements must be continuously balanced.

Within the Lesotho Highlands system, Katse Dam has decreased slightly from 99.8% to 99.6%, remaining just below full capacity. This reflects a controlled balance between inflows and water transfers to South Africa.

Meanwhile, Mohale Dam declined marginally from 102.8% to 102.7%, but remains above capacity, indicating that inflows continue to sustain elevated levels despite ongoing releases.

The Department of Water and Sanitation will continue to closely monitor reservoir levels and implement necessary control measures to ensure dam safety and optimal water distribution.

The Department further reiterates the importance of responsible water use, even during periods of apparent abundance, to safeguard long-term water security amid changing climatic conditions.