The Department of Water and Sanitation (DWS) will open five sluice gates at the Vaal dam on Monday following heavy rainfall in Gauteng, a spokesperson confirmed to Engineering News.

According to VBHydrology, which publishes updates on its reservoir.org site from the DWS’s flood monitoring and forecasting office, the gates are being opened in hourly intervals throughout the day between 09:00 and 13:00.

All valves will be closed.

The DWS will publish an updated statement in due course.

In a statement issued on Sunday, the DWS said that it had pre-emptively increased water outflows at the Vaal and Bloemhof dams, as Gauteng experienced heavy rainfall over the weekend.

The water outflow at the Vaal dam was increased from 17 mᵌ/s to 60 mᵌ/s, while at the Bloemhof dam, the water outflow was increased from 60 mᵌ/s to 120 mᵌ/s.

As the rainfall continues, most of the dams will also experience high volumes.

Both the Vaal and Bloemhof dams have respectively recorded 104.07% and 98.88% on Sunday. By Monday morning, this had increased to 107.4 % and 99.9%.

“The outflows are necessary to manage the river systems for the potential increases in inflows into the catchment, owing to continuous rainfall, but it should be noted that while the outflows are significant, they will not cause the river to overtop the banks,” the department said at the time.

The DWS will continue to actively monitor the inflow water levels at both the Vaal and Bloemhof dams to ensure that necessary precautions are in place in line with dam safety standards and hydrological monitoring systems, to safeguard and maintain the integrity of the water resource infrastructures, as well as to reduce flood conditions while keeping the dam at full capacity.