Cape Town's July rainfall way below average
31 July 2018
Rainfall in Cape Town's water catchment areas was way below average during July, with one weather station recording less than a third of the normal July rainfall.
Rainfall in the Jonkershoek mountains, between the Berg River and Theewaterskloof dams, was 170mm for July, compared to the long-term July average of 535mm.
Experts say what happens in August and September will determine the extent to which Cape Town and surrounding areas will be able to recover from the three-year drought.
The average level of Cape Town's supply dams is 56.8% of storage capacity, an increase of 0.4% from last week.
The average level of dams throughout the Western Cape is 51%.
Rainfall in the catchment area
Nicky Allsopp, head of the fynbos node at the SA Environmental Observation Network, described the low July rainfall as "very worrying".
"The cold front systems are coming through, but they are being pushed south so it is raining out at sea and not on land. Over the last four weeks the increase in dam levels has almost gone flat so we are certainly not out of trouble yet.
"We are nowhere near as bad as we were this time last winter, but at 56% we are still teetering. We won't know exactly what the situation will be until we have had a full winter and seen what rainfall materialises during August and September," Allsopp said.
May and June rainfall in the catchment area was good and saw dam levels rise rapidly from a low of 20% in early May.
Rainfall at Jonkershoek station in May was 357mm, close to the long-term average for May of 400mm, and in June was 565mm, more than the long-term average for June of 500mm.
Allsopp said winter in 2017 had also seen good rainfall recorded in the Jonkershoek mountains in June – 536mm – that had then dropped to 181mm in July. But in August, it jumped to 399mm.
"How we get through next summer will very much depend on how much rain we get in August and September."
Allsopp said the region was entering the fourth year of "strange rainfall patterns" in winter.
"It is not long enough to say this is evidence for climate change, but we have had an extreme reduction in rainfall these four years. In the 1920s we had long periods of low rainfall in Cape Town, but then the reduction compared to the long-term average was not as much as it has been these last few years," Allsopp said.
Kevin Winter of UCT's Environmental and Geographical Science said Cape Town was now in "a bit of a holding position".
"It is very uncertain what August will bring. We're not seeing anything major now in terms of supply, as July rainfall was below normal. Our dams are about the same as they were this time in 2015, but now the water demand management is better," Winter said.
Water quality
What was important now was to shift the conversation from water supply to water quality.
Some of the rivers in the country and locally were so polluted, it was "horrific".
"It is incredible that we can't shift the conversation towards water quality. It seems there is no political will to address that."
Capetonians' average water consumption decreased by 32 million litres to 498 million litres a day last week.
The City of Cape Town said on Monday that its June water map showed that a record number of 400 000 households had achieved "green dot status" for water saving. About half of these used less than 6000 litres a month.
Deputy Mayor Ian Neilson congratulated Capetonians and said this was "exactly what we need to help us navigate the climatic uncertainties".
"Given the warm, dry weather over the past two weeks, the City's pressure management initiatives and the water-saving efforts of its residents remain critical," Neilson said.
Go to www.capetown.gov.za/watermap to view the latest map showing water use of individual households. Flats and cluster houses are not shown.
