The Department of Water and Sanitation (DWS) has opened five sluice gates at the Vaal dam on Monday following heavy rainfall in Gauteng.

The gates were opened in hourly intervals between 10:00 and 13:00, increasing the water outflows from 60 mᵌ/s to 700 mᵌ/s.

All valves at the dam were closed.

The department also increased the outflows of the Bloemhof dam to 250 mᵌ/s at 10:00 and to 400 mᵌ/s at 14:00.

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 108.4 % 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 warned, however, that owing to the increased water releases by the five sluice gates, there may be possible overflowing of the riverbanks downstream, and this may affect infrastructure built in lower-lying areas within the floodplain and communities are urged to be alert to the rising water levels.

The Department of Water and Sanitation further cautions communities around the Vaal Triangle, Parys and low-lying areas next to the river to be cautious, and farmers that have pumps and infrastructure directly next to the river are urged to take steps to safeguard them.

Those residing in the riparian areas of the Vaal River are also urged to be alert and remove valuable equipment, movable infrastructure and livestock as river levels may continue to rise.

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.