As the water levels of the Vaal dam reach 101.51%, the Department of Water and Sanitation (DWS) has reduced the outflow of water from 61.2 cubic metres a second (mᵌ/s) to 40 mᵌ/s as inflows slightly decrease.

This followed the DWS’s efforts last week to slowly release some of the water using five of the eight valves at the dam to ensure that there is balance between the inflows and outflows amid heavy rainfall.

“The outflow release of water from the dam is one of the measures 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 infrastructure, as well as reduce flood conditions while keeping the dam at full capacity,” the DWS said.

These releases, while normally ranging 16.8 mᵌ/s to 17.6 mᵌ/s using two valves range to keep the natural flow in the river, aim to ensure that the dam’s capacity stays within the range of 100% to 103%.

The water flow remains insignificant and will not overtop the banks.

The water levels of the downstream Bloemhof dam reduced slightly to 99.44%, with the controlled outflow releases of 320 mᵌ/s through outlet pipes remaining unchanged to facilitate the proper management of water levels and to keep the dam at or below its full supply capacity of 100%.

Neither dam has opened their sluice gates.

“The DWS continues to monitor the hydrological monitoring and forecasting systems in the Vaal river system and if inflows increase, and should the need arise, more releases may be effected on both dams to safeguard to prevent dam failures and major disasters.”