The water and sanitation department has opened three sluice gates at the Vaal Dam and two more will be opened on Friday.

The recent heavy rainfall over many parts of the country resulted in the dam reaching just over 106% capacity. The last time the dam was this full was in 2017.

According to the department, the water was released from the dam in anticipation of more rainfall expected over the Orange River System (ORS).

The department said two more gates would be opened on Friday.

One of the gates will be opened at 10am, followed by the second at 12pm, with the total outflow expected to be about 649m³/s.

“Initial analysis had indicated that there was a need for the opening of three gates. However, the latest analysis showed that there was a need to open two more.

“The release of the water, which will flow into the Bloemhof Dam, is in anticipation of rainfalls expected over the ORS and the river flows from the Upper Vaal rapidly filling the Integrated Vaal River System and particularly the Vaal Dam,” said the department.

According to the department's spokesperson, Sputnik Ratau, there was a need to accommodate the expected rains that would have an effect on the ORS in the next few days, as well as adding to the already rising water levels in the system.

Ratau said the opening of the sluice gates was to release water to protect infrastructure and to ensure that the Vaal Dam continued to operate optimally.

Earlier this week, the department reassured the public that the dam would not collapse under the additional pressure.

Director in the dam safety unit of the department, Wally Ramokopa, said the likelihood of dams collapsing from the ongoing rainfalls was unlikely as their infrastructure is built to withstand heavy rains and flooding.

“There is no need for people to be alarmed about possible water infrastructure collapse,” he said.

Ramokopa said dam owners are required to arrange for the execution of a formal dam safety inspection by an approved professional person (APP) at least every five years.

“When carrying out the five-yearly safety evaluation, the APP will conduct a flood frequency analysis to check whether the dam is able to route through different flood occurrences. This helps us to anticipate whether the dam would be overtopped should a certain size of a flood occur or potentially damage the dam,” he said.