Heavy rain brings relief but lots more needed A DAM SIGHT BETTER
THE DARK, heavy clouds gathered while the group stood on the Vaal Dam wall as a light drizzle began to fall.
On prior visits to the Vaal Dam, in August and November last year, The Star witnessed the clear skies with no rain in siight as the sun beat down on the drying riverbed.
Between January and November last year, the Vaal Dam was dropping at an extreme rate. At the time, the consulting officer for the Department of Water and Sanitation (DWS) at the Vaal, Pieter Vermaak, said they were losing about 10cm a day, which was a significant amount.
At the end of August the Vaal was on 33.7 percent, and two months later it dropped to 26 percent.
However, water released from Sterkfontein Dam between November 7 and December 22 as well as several days of constant heavy rainfall in the area over December and this month have painted a different picture.
The Vaal is now sitting at 52.9 percent. Islands and riverbeds that were once visible during prior visits are now almost covered, and the area is greener. But this doesn’t mean Gauteng residents can relax their efforts to use water wisely.
On the contrary, if Gauteng is going to get through winter without further restrictions, residents must continue to be careful with their water usage and adhere to the level two restrictions.
DWS deputy director-general of emergency projects Trevor Balzer said that although the Vaal Dam had picked up a significant amount of water over recent weeks due to the heavy downpours, Gauteng was far from being out of the woods.
“About one in every five people in Gauteng receives water from the Vaal Dam. Pretoria receives about 85 percent of its water from the Vaal Dam, but the run-off in northern Joburg and Pretoria flows into rivers like the Jukskei and Crocodile, which lead to Hartbeespoort Dam.
“The rain that falls in southern parts of Joburg, Gauteng and the Wilge River area in the Free State is what supplies the Vaal Dam,” he added.
He said the DWS needed municipalities to save 15 percent of water. Municipalities not faring well in water saving included Midvaal, Madibeng and Ekurhuleni.
“However the City of Joburg has managed to save 14.4 percent and is just below the line, while Pretoria has saved 21.1 percent,” Balzer said.
The SA Weather Service explained to the DWS that with the La Niña weather phenomenon returned to neutral, it was difficult to predict, but South Africa could see above normal rainfall in the next few months, and “We need a significant amount above that”.
“We need another 10 rainfalls like we had in the last week to take us out of the drought system,” he said.
Balzer emphasised that the Vaal Dam was not the only indicator when looking at water supply levels for Gauteng.
“The Vaal river system consists of 14 dams, with the Vaal Dam being just one. When people ask why the restrictions haven’t been lifted if the Vaal Dam is rising, we need them to remember it’s just one of 14 dams supplying Gauteng.
“Before we can look at lifting restrictions, we need the level of the Vaal River system to be at 70 percent or above.”
He added that the DWS would review whether to maintain water restrictions in municipalities after May.
As a clap of thunder was heard overhead, Balzer explained that even during cloudy conditions there was evaporation over the Vaal Dam.
“It’s shallow and wide, so this leads to a much higher evaporation rate.
“But Sterkfontein (Dam) is in a cooler area, it’s small and deep, so it has a much lower evaporation rate, but it takes longer to fill up,” he said.
Spokesperson for the DWS Sputnik Ratau said the level of the Vaal Dam was at 44 percent full last Friday but had increased to 52.8 percent because of the rainfall.
While standing on the dam wall he pointed to a grey building in the distance where the water from the dam only reached its bottom. “It should be up to the middle of that structure, so you can see we still have a way to go.
“We need significantly above normal rainfall. We have to remember that with high temperatures there is also a high evaporation rate. The more rain we get, the better,” he said.
“We need to take the municipalities’ message seriously. We must listen to the message being conveyed, use water sparingly and bring water consumption down,” Ratau concluded.
As the group headed back to Joburg and Pretoria, the heavens opened and rain began to fall heavily once more.