Below-normal summer rain predicted as dam levels decrease

rain gauge drought conditions
Although dam levels are currently deemed comfortable, there is a lot of uncertainty about what the weather will do in the coming summer season.
Photo: Sabrina Dean

Although water supply scenarios for much of the country are currently deemed comfortable, forecasts of a chance of below-normal rainfall for early summer do not bode well for parts of the Eastern Cape and Limpopo where rivers are reportedly drying up.

According to the weekly status report of the Department of Water and Sanitation (DWS), South Africa’s dams are currently at 64% full, down from over 74% at the same time last year.  DWS spokesperson Sputnik Ratau told Farmer’s Weekly that while supply levels were still deemed comfortable for much of the country, there were pockets of concern, especially in Limpopo and the Eastern Cape.

“We have some areas where the rivers do not have much water and others that are actually dry. We have some rivers at about 2% and others at 7%,” Ratau said.

He said when river levels fell so low it was virtually impossible to continue to abstract water, even to operate water treatment plants. High temperatures were also leading to increased water use and loss through evaporation.

The SA Weather Service (SAWS) was meanwhile predicting the chance of less rain than normal in spring and early summer, moving towards wetter conditions by midsummer.

SAWS scientist Cobus Olivier said their latest models were pointing to the chance of a drier start to the summer rainfall season during the last three months of 2019. He pointed out, though, that the forecast remained very uncertain.

“It looks as if most forecasts are agreeing that the start of summer might be drier than normal.”

Certainty of the forecast was hampered by the fact that the El Niño-Southern Oscillation (ENSO) was currently in a neutral phase, said Olivier.

“Usually when it is neutral our forecasts are more uncertain. If it was in an El Niño or La Niña (phase there would have been more certainty about the forecast.”

Olivier was advising farmers to proceed with normal summer season planting preparation, but to incorporate conservative planning measures taking into account that early summer could be drier.

The latest climate advisory released by the agriculture department on 9 October highlighted that drought conditions were still persisting in some parts of the country, with water restrictions still in place in several provinces.

“The average level of major dams has increased in the Western Cape, but decreased in other provinces,” the department said.