Water and Sanitation on third sluice gate re-opened at Vaal Dam increasign outflow at Bloemhof Dam

The Vaal Dam is currently experiencing high inflows due to the heavy rainfalls on the upper catchment, as such the Department of Water and Sanitation (DWS) has re-opened a third sluice gate today at 16:00 to manage the water outflows.

The dam operated with two sluice gates since last week, on 16 April 2025, and the opening of the third sluice gate will increase the outflow from 299.59 cubic metres per second (m3/s) to an estimated 400 m3/s.

The current water inflow is estimated at 943 m3/s and the water level at the dam is at 108.4% as of midday. There is a possibility that another sluice gate will be opened tomorrow should the inflows continue to increase.

At Bloemhof Dam, water outflows were also increased from 500 m3/s to 650 m3/s today at 10:00, and again to 800 m3/s at 12:00 in anticipation of the measured incoming flows upstream. These adjustments are necessary to manage the continuous rising inflows and safe operation of the dam which is at 106.71% today. Inflows into the dam are estimated at 640 m3/s as of this afternoon and are likely to increase over the next 24 hours. As such, there are potential plans to further increase releases tomorrow morning.

All the sluice gates remain closed at Grootdraai Dam, and the storage capacity is still at 104.92%, with inflows of 32.44 m³/s.

The controlled water releases at both the dams have led to overtopping of riverbanks downstream, resulting in flooding that has affected settlements that are in the lower-lying areas within the 1 in 100-year floodline.

People living within the floodline of the Vaal River downstream of the Vaal and Bloemhof Dams and have evacuated should continue to avoid the flooded areas as the river catchment remains oversaturated.

With more rainfall predicted in the Upper Vaal Catchment, the DWS will continue to monitor inflow water levels in the Integrated Vaal River System (IVRS) to ensure that necessary precautions are in place in line with dam safety standards and hydrological monitoring systems to safeguard infrastructure and attenuate any flood conditions.

As part of the dam safety protocols, sluice gates are opened for controlled water releases when dams breach the full capacity mark, to prevent the water resource infrastructure from failing as it may lead to a dam bursting and causing a disaster of unimaginable magnitude. The Department implements these necessary controlled water releases at the dams as part of dam safety precautions to safeguard the infrastructure and protect human life. 

For more information, contact:

Head of Communication, Dr Mandla Mathebula 
Cell: 083 235 8675
E-mail: MathebulaM4@dws.gov.za

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