Sluices stay closed as Vaal Dam reaches 100% capacity 

Consistent, above-average rainfall has boded well for most provinces in South Africa, notably areas that do not receive much rainfall at this time of the year. 

In Gauteng, the results are tangible, with the Vaal Dam reaching 100% capacity for the first time since 2017.

The dam currently sits at 101%, and was at 100% on Monday, the Department of Water and Sanitation’s spokesperson, Sputnik Ratau, said. 

Boats parked in the Manten Marina are seen on 3 February 2021 at the Vaal Dam after a period of heavy rains. The dam is filling up quickly at the moment and is currently at 82%. Picture: Michel Bega

100% capacity does not mean that the sluice gates will be opened yet, however. 

Ratau said South Africa’s dams were built with a design capacity to allow at least 120% of water, or more, before the decision to open the sluices is made. 

ALSO READ: Why the Vaal Dam doesn’t fill up after every thunderstorm

“As the [department] ordinarily manages the dams, a lot of information and consideration takes place to inform whether that happens or not. We are not considering opening the sluices yet. We’re not yet there,” Ratau explained. 

How much rain has fallen? 

Towards the end of January and into February, many parts of the country had experienced above-normal rainfall. 

The Hartbeespoort Dam can be seen flowing into the Crocodile River on 5 February 2021, North West. Picture: Jacques Nelles

South African Weather Service (SAWS) forecaster Kgolofelo Mahlangu provided The Citizen with some of the most significant rainfall averages for January until 1 February:

Tshwane 

• Bronkhorspruit: 127mm
• Irene: 149mm
• Pretoria near Unisa: 148mm
• Pretoria near the University of Pretoria: 185mm

Johannesburg

• OR Tambo International Airport: 85mm
• Lanseria: 128mm

Mpumalanga

• Belfast: 202mm
• Ermelo: 285mm
• Komatidraai: 217mm
• Kruger Mpumalanga International Airport: 231mm
• Nelspruit: 231mm

Limpopo

• Luvuvhu: 250mm
• Venda: 394mm
• Thohoyandou: 323mm
• Tzaneen: 330mm

North West

• Taung: 200mm
• Hartbeespoort: 137mm

Free State

• Fauresmith: 218mm
• Wepener: 294mm

Northern Cape

• Kathu: 217mm.

Dams will not collapse 

The department has assured that South Africa’s dams are made to last. 

The department’s dam safety regulate unit director, Wally Ramokopa, said that the country’s more than 5000 registered dams “stand strong”, even in the face of spillages due to heavy rains. 

Two sluice gates of the Vaal Dam were opened on Sunday, 26 February 2017. File image.

The Hartbeespoort Dam can be seen flowing into the Crocodile River on 5 February 2021. Picture: Jacques Nelles

Ramakopa said since tropical storm Eloise reached South African shores, only two reports of potential damage to water infrastructure were received by the department. 

These were the Pioneer Dam in the Kruger National Park, and a barrage in Phalaborwa. 

ALSO READ: Stern warning for people around Vaal Dam as water levels rise

“At Kruger National Park, the dam had reached 100% capacity and there were fears that the spillway may not be sufficient, however, the dam was able to safely route the floods without causing any damage,” Ramokopa said.

And in Phalaborwa, a radial gate failed after being opened in the barrage, to release water during flooding as a result of the cyclone. 

A flooded area near a rural village just outside the Kruger National Park in Pafuri, Limpopo, on 25 January 2021. The area of Pafuri measured 88mm of rainfall by 10am the previous day. Picture: Jacques Nelles

⚠️ALERT⚠️
Numbi gate is closed due to flooding. pic.twitter.com/RirXAvLhHy

— Kruger National Park (@SANParksKNP) February 7, 2021

“There is no need for people to be alarmed for possible water infrastructure collapse,” Ramakopa assured, adding that the department enforced compliance for dam owners to conduct safety inspections at least every five years. 

During these inspections, a flood frequency analysis is done, to check if the dam is able to route through different flood occurrences. 

The information gathered in these inspections allowed the department to “scrutinise the reports and gather data” to see if a dam could withstand the pressure of water behind the dam’s concrete wall or earth embankment wall. 

“It is from then that we are able to predict possibilities of any movement or slip failure when the dam is full,” said Ramokopa.

Dam owners were also given recommendations, and if they were found to have defaulted, the department said it would “act on them as they are putting the lives of others at risk”. 

Forecast for the week 

Over the next seven days, weather in most parts of the country could be cloudy with a chance of afternoon thundershowers. 

Kokotela informal settlement in Lawley, Johannesburg, flooded on 8 February 2021. Residents vacated their homes after being submerged in water. Rains have left Gauteng and other province’s people homeless. Picture: Nigel Sibanda

Mahlangu said no extreme weather was expected now that the country was back to its normal afternoon storms. 

There is a chance of thunderstorms over the western parts of KwaZulu-Natal, spilling into the northeastern parts of the Eastern Cape, later on Tuesday. 

For the rest of the week, provinces along the eastern parts of the country and along the south coast could expect 30% to 60% afternoon showers and thundershowers. 

Mahlangu said Gauteng, Limpopo, Mpumalanga, North West and Free State could expect clear morning skies, followed by cloudy conditions, leading into afternoon showers. 

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