NEWSFLASH
Vaal Dam releases water after reaching 106% capacity – a first since 2017
The Department of Water and Sanitation released water from the crucial dam on Thursday after it reached 106% capacity, as heavy rain from Tropical Storm Eloise raised dam levels across the country.
Despite the devastation of Tropical Storm Eloise, heavy rains have brought relief to some of the country’s dams.
On Thursday, the Department of Water and Sanitation (DWS) opened three sluice gates to release water from the Vaal Dam, which had reached 106% capacity by that morning.
Crowds stopped on the side of the road to watch the gates open. While some took pictures, others marvelled at the torrent of water flowing through.
DWS spokesperson Sputnik Ratau said water was released to mitigate river flows from the Upper Vaal, which were rapidly filling the dam.
“… any further rapid inflows, especially as current indications are concerned with regard to the developing system in the Mozambican Channel, with the likelihood of it delivering more rain in the Upper Vaal, have impressed upon the DWS hydrologists to relook at the management of the Vaal Dam in this way,” said Ratau.
The Vaal Dam had already reached 100% capacity by late afternoon on Monday. Photo: Felix Dlangamandla/Daily Maverick
The Vaal Dam, which forms part of the Integrated Vaal River System (IVRS), had already reached 100% capacity by late afternoon on Monday, 8 February. This is the first time the dam has been full since 2017.
Gauteng, the Free State, North West and Mpumalanga depend on the IVRS, which has a network of 14 dams. It is crucial for the economic hub of Gauteng and supplies water to key industries such as Sasol and Eskom.
Daily Maverick previously reported the dam was 79.8% full in the first week of February. A year ago it was a mere 57%.
This follows Tropical Storm Eloise which made its way from Mozambique and in late January struck north-eastern provinces in South Africa, including Mpumalanga, Limpopo and some parts of KwaZulu-Natal, destroying homes and infrastructure and leaving more than a dozen people dead.
The opening of the sluice gates drew a crowd on Thursday. Photo: Felix Dlangamandla/Daily Maverick
Now, heavy rainfall has seen the county’s average dam levels rise from 62.1% at this time last year to about 88%.
Dams such as Bloemhof, which borders North West and the Free State, reached 110% capacity on Wednesday. Last week, the Gariep Dam was 112.9% full.
Ratau told Daily Maverick that concerns that additional water pressure would cause the dam to collapse were unfounded.
“When we prepare to build a dam, part of what gets into the design is an allowance for even more water than the dam can accommodate.”
In the case of the Vaal Dam it was an additional 20% to 26%.
“We are still well within the capacity”. DM
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No potential for hydro power here ?
To generate significant hydro power one needs either a high head or a high flow rate, with different turbine designs in each case. The head on these dams is low. The flow is (usually) low. So it’s unlikely to be economic to install anything other than a very small power generation system, too small to make a big difference to Eskom.
OK, Thanks. As an electrical engineer you are surely familiar with these issues. On hindsight, a too quick and poorly thought through question, as I had long observed that all dams for hydro power are high, mostly situated in more mountainous areas, with larger and steeper drops of the water masses. And obviously the Vaal dam does not open the sluices very often, so it does not have that much water to use for energy production, as I guess most water is pumped towards the GP urban areas for drinking water, or evaporates or disappears as ground water.
Anyway, we need to explore every avenue for clean, sustainable electricity generation, as the old Eskom power stations fail dismally.
Maybe a business case can be made for FPV, floating solar, which is now being constructed in many parts of the world. It is obviously a bit more expensive to construct, 10-20%, but the cooling effect of the water renders the solar panels more effective, reduces water evaporation, and on the water of hydro dams, the power lines are already there. Vaal dam is less than 30 kms away from the Lethabo power station.
And it is proven that PV solar on the highveld is in winter more effective than in the NC. Already earlier people have argued that large solar power farms could be constructed on the sites of the soon to be decommissioned coal fired power stations and nearby mines.
There’s a very small hydro plant at the outlet of the Lesotho Dam tunnel, between Clarens and Bethlehem. That has less than 10MW of generating capacity but can run throughout the year because the flow is guaranteed whereas the Vaal will have very low outflows for much of the year.
Any idea of the capacity of the Muela hydro power station, just south of that area, but in LS, being run from the same water flow from Katse dam ?
Working in MSU in 2008, when SA was experiencing loadshedding, and there was none across the border in the Mountain Kingdom, somebody of LEC, Lesotho Electricity Company, told me that LS could in summer when the demand was lower almost solely rely on power from Muela, and hardly had to import any from SA. LS never has loadshedding, and electricity is cheaper there.