Why the Vaal Dam is not filling up, despite heavy rainfall

Gauteng residents are being urged to continue to use water sparingly. Image: Randburg Sun

Recent rain will not cause immediate change to Vaal Dam levels as the water does not flow into it directly.

According to Rand Water, dam levels stood at 39% on Monday, whereas during the same time last week, it was at 40.8% capacity, reports Vaal Weekblad.

The utility said there were a number of factors that contributed to the rise and fall of dam levels.

“The first rainfall soaks into the ground and fills depressions like farm dams before it runs off to our rivers and dams.

“In order for there to be an increase in dam levels, there would have to be continuous rain over a period of time,” read a statement from the utility.

Rand Water said the recent rain would not cause immediate change to Vaal Dam levels as the water did not flow into it directly.

ALSO READ: Water department says the rain mostly all fell in the wrong places

“None of the water we have had in Gauteng goes to the Vaal dam, so there will be no immediate effect.

“The water either flows towards the Crocodile and Jukskei Rivers or it joins the Vaal River downstream of the Vaal Dam to go towards Bloemhof Dam,” said Rand Water.

The latest report by the department of water and sanitation (DWS) on dam levels recorded an average of 56.1% capacity of water that is currently available in the country’s reservoirs, a drop of 10% compared to the same period last year, reports Caxton Central.

South Africans are pinning their hopes on the current heavy rains that have been pouring since last week and are expected to subside by the weekend.

Water that is stored in the country’s reservoirs was calculated at 17,964.4 million cubic metres, slightly above half the full capacity of 32,012.1 million cubic metres. However, hydrologists are hopeful that the current levels will improve drastically when the above-average heavy rains begin to drench most parts of South Africa by mid-December. They are predicting that some regions will be flooded from the heavy rains, a situation that can become untenable.

As a precaution, the eThekwini Metro Council in KwaZulu-Natal warned communities that live on the banks of rivers to move to safer areas to avoid being flooded. Floods, thunderstorms and tornadoes claimed the lives of 80 people, while 700 were displaced in the province last month. As a result, motorists and pedestrians were warned against crossing flooded rivers and bridges.

People in Tshwane also experienced heavy floods this week. The City of Tshwane said about 280 lives had been saved during heavy rains that killed two and left hundreds displaced.

The water situation in Mopani District in Limpopo continues to be a source of concern as the Tzaneen Dam slid to 5.1% this week. There is virtually no drop left in Middel-Letaba Dam, a stone’s throw from Tzaneen, where the water level dropped to 2.8%. Residents of Tikkie Line Village that depend on Middel-Letaba now rely on tanker water for survival.

The water situation in KwaZulu-Natal is expected to improve slightly in the next few days as the province is currently receiving 80% rainfall. Midmar Dam in the Natal Midlands is expected to increase its volumes from the current 91.2% level.

“Despite the current rainfall, the department would like to warn South Africans against complacency and it encourages citizens to continue with saving water,” said the DWS.

On Thursday morning, news about the Vaal Dam became slightly more positive, with Gauteng Weather tweeting that the Vaal Dam is back above the 40% full mark.

This is apparently due to water being released from the Grootdraai Dam, which stood at 75.3% on Tuesday, but has allegedly experienced increased levels, making its current levels at 102%. This however has yet to be verified by the DWS website, with readings updated last on Tuesday.

Rand Water tweeted on Thursday morning that Vaal Dam levels had increased by a dismal 0.59%.

Here is your weekly dam update:

  • The Vaal River System consisting of 14 dams serving mainly Gauteng, Sasol and Eskom is at a total of 111.3%.
  • The Cape Town Dam System, consisting of six dams serving mainly the City of Cape Town, is at 61.9% this week.
  • The Eastern Cape Dam System is at 47.2% while KwaZulu-Natal sits at 53.4%.

Here are the latest dam percentages throughout the country:

For a more in-depth rainfall update, visit WeatherSA. For more information on the water storage levels across the country, visit the DWS site.

Figures will be updated as more information on current dam levels are made available.

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