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South Africa

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.
Vaal Dam releases water after reaching 106% capacity – a first since 2017 The opening of the sluice gates drew a crowd on Thursday. Photo:Felix Dlangamandla/Daily Maverick

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

Comments (1)

Marcel Anceaux Feb 11, 2021, 04:07 PM

No potential for hydro power here ?

mike muller Feb 11, 2021, 08:54 PM

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.

William Stucke Feb 11, 2021, 04:43 PM

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.