Rapidly rising inflows into the Vaal dam have necessitated the opening of four more sluice gates on Friday.

This will bring the total number of gates open at the dam to ten.

Above-average continuous rainfall has led to heavy inflows on the already saturated upper catchments.

More inflows into the dams are expected, particularly the downstream Bloemhof dam, with outflows potentially increased later on Friday or Saturday.

The Department of Water and Sanitation (DWS) will be opening the four sluice gates gradually in hourly increments until 13:00 on Friday.

The water level of the Vaal dam is currently sitting at 118.48% with an inflow of 2 448.24 cubic metres per second (m³/s).

At Bloemhof dam, water outflows are also being increased in two-hour increments from 2 000 m³/s to 2 800 m³/s by 15:00.

The dam level is currently sitting at 110.27%.

"These adjustments are necessary to manage the continuous rising inflows and safe operation of the Vaal and Bloemhof dams," the DWS said.

At Grootdraai dam, the already opened gate has been increased to three metres, owing to the higher inflows of 967.47 m³/s, with a second gate opened to 1 m.

The storage level is at 110.08%.

In the Orange river, the water levels of the Gariep and the Vandekloof dams are currently sitting at 108.25% and 106.09% respectively and overspilling.

"The controlled and uncontrolled water releases at all these dams will lead to overtopping of riverbanks downstream of the Orange and the Vaal rivers, resulting in flooding of settlements that are in the lower-lying areas within the 1-in-100-year floodline.

"People living within the floodline downstream of the Vaal and Bloemhof dams, and who have had to evacuate, should continue to avoid the flooded areas as the river catchment remains oversaturated," the DWS warned.