Watershed: A video showing damage to the wall of the Bloemhof Dam
Water levels at the Vaal Dam have continued to rise, and were sitting at nearly 113% of capacity on Tuesday, according to the department of water and sanitation.
It has advised people living within the floodline of the Vaal River, downstream of the Vaal Dam and the Bloemhof Dam, to evacuate and move to a safe area. Residents should also remove valuable equipment, movable infrastructure and livestock.
“The Vaal Dam continues to rise with water levels at 112.85% and 1 248.11mᵌ/s [cubic metres a second] inflows from the upper catchment,” department spokesperson Wisane Mavasa said.
“The five sluice gates remain open with a discharge remains of 793mᵌ/s to manage the water levels at the dam.”
She said the controlled water releases at both the dams may lead to “possible overtopping” of riverbanks downstream. This would affect infrastructure built in lower-lying areas within the one-in-100-year floodline.
One sluice gate remains opened at 2.5m to enable water releases at Grootdraai Dam in Mpumalanga in the upper Vaal River catchment, upstream of the Vaal Dam. The dam was recorded to be at 101% full supply capacity on Tuesday.
In Orkney, in North West, several homes on the banks of the Vaal River were evacuated at the weekend.
Storm Zurcher, who has a property downstream of the Vaal River, said he was not worried. “There’s a couple of places that are underwater on the other side of the barrage but … they’ve got it under control. If the Rietspruit was in flood, I would be worrying right now but I think they’ve released water early enough.”
At the Bloemhof Dam, the department has increased water releases to 3000mᵌ/s to manage the rising dam levels, which were standing at 116.5%. “These adjustments are necessary to manage the sustained high inflows and ensure safe operation of the dam,” said Mavasa.
To manage the rising levels of water at the Bloemhof Dam, five radial gates have been opened — three of the gates are fully opened and two are partially opened at different metres.
Mavasa noted that the Integrated Vaal River System is experiencing high inflows, “which dictates that dams within the system have to be on high alert and implement the dam safety protocols based on the levels of water”.
The department is monitoring inflow water levels to ensure that precautions are in place.
As part of dam safety protocols, sluice gates are opened when dams breach the full capacity mark and overflow to prevent the infrastructure from failing, which may lead to a dam bursting and “causing a disaster of unimaginable magnitude”.