Two Nelson Mandela Bay supply dams are overflowing, more rain expected, but crucial reservoir is only 24% full

Two of the Nelson Mandela Bay metro’s catchment dams are more than 100% full, and more heavy rainfall has been predicted for the region for this weekend.

Garth Sampson from the South African Weather Service said they were expecting above-normal rainfall in the catchment area until November.

“However, moving into summer, totals will be below the norm. Considering this is our dry season and high usage season, it will put a strain on water resources. Going back to spring, models are expecting some follow-up rain this weekend and maybe even next week later.

“The amount of rain received in October will heavily influence the decision-makers at the Department of Water and Sanitation and ultimately the metro as regards water restrictions,” Sampson said.

The region has been in the grip of a devastating drought for the past eight years.

Read more in Daily Maverick: Nelson Mandela Bay walks tightrope of a wing and a prayer – and then finally … rain

The Gamtoos Irrigation Board said on Wednesday, 4 October, that the Kouga Dam was 101% full and 29,820 litres per second were spilling over the dam wall.  

Water is still flowing fast into the dam at 17,430 litres per second at Stuurmanskraal and 3,800 litres per second at Groot River’s weir.

The Churchill Dam is also full. The smaller Loerie and Groendal dams, both balancing dams and not true catchment dams, are also full.

But the Impofu Dam, a crucial dam in the water reticulation system, is still only 24% full. It is expected to fill up faster now that the Churchill Dam, which was built upstream from Impofu, is full.

The metro’s executive mayor, Gary van Niekerk, said combined dam levels shot up drastically from 48% to 71.73% in a week, and this has eased the steely grip of an eight-year drought.

“We are relieved that four of our major supply dams are 100% full, but do not anticipate water restrictions to be eased by the Department of Water and Sanitation, because the Impofu Dam is currently still at 24.7%,” he said.

“Since Impofu is three times the size of the Churchill Dam and receives greater volumes of water when the Churchill overflows, we need more persistent rains for this dam’s level to improve drastically.

“Impofu is also the biggest dedicated water resource for consumers of the Nelson Mandela Bay Municipality.

“The Department of Water and Sanitation will use their models to assess the impact of the rainfall and engage with us regarding the way forward,” Van Niekerk said.

“The Kouga Dam, Churchill, Loerie and Groendal dams are all at 100%, a major change in fortunes for the municipality and its residents,” he said. DM