Rain over the weekend that caused flooding in some parts of Cape Town and snowfall along the Cape fold mountains nudged the level of the City‘s storage dams up to 62% on Monday.
This is an increase of 1.9% in a week.
Because of the rise in the dam levels, the City of Cape Town has asked the national Department of Water and Sanitation to reduce its water restrictions from 45% to 40% for the City and from 60% to 50% for agriculture.
The City made the proposal at a meeting with the national department and other water users, agriculture and municipalities on Friday.
The national department said it would give an answer by the end of the month.
The national department decides on the amount of water that towns, cities, agriculture and industry can use, and imposes percentage cuts in times of drought. Because of the Western Cape‘s three-year drought, the national department told agriculture to cut consumption by 60% and the City by 45%.
Drop in water consumption
It is then up to municipalities, irrigation boards and other bodies to translate the bulk water cuts into detailed water restrictions.
Capetonians‘ water consumption, which had been steadily increasing over the last three weeks, has dropped from 527 million litres a day last week to 513 million litres a day on Monday.
The rain station in the Jonkershoek mountains, part of the storage dams‘ catchment area, had received 95mm of rain by Saturday evening, which was about 20% of its monthly average for August.
Some of the smaller dams are full or nearly full, but of the three big dams, only the Berg River Dam is nearly full at 93% of its storage capacity.
Of the other two big dams, Voelvlei is 66.3% full and the biggest, Theewaterskloof, is 45.6%.
Cape Town‘s water supply is a lot better than it was this time last year, when dams stood at 34%, and is about the same as it was at this time in 2016, when levels were just under 60%.
No resilience for another dry year
As the snow melts in the mountains that form the catchment area for Cape Town, the dam levels will continue to rise slowly.
Nicky Allsopp, head of the fynbos node at the South African Environmental Observation Network, said August was the last of the main winter rainfall months, with September getting on average about two thirds to half of the rainfall that August normally gets.
“So it is concerning that at this stage we still have not got the average amount of rain we normally get in August. What we‘ve had has not added up to a good month. There were good rains early on in the season, but the rate at which dams are filling has slowed down,” Allsopp said.
Because of this, consumers had to continue being frugal with water.
“We will get through the summer – barring everyone deciding they can take 20-minute showers every day – but what we don‘t have is resilience in the water system to see us through if we get another dry year.”
Dams in most of the rest of the Western Cape are looking good, with the average level for the province at 55% of storage capacity – way up from the average of 16% around the end of April.
The drought-stricken areas in the province are the Karoo and Gouritz River catchment areas, where the average dam level is only 18% of storage capacity.
According to the City of Cape Town, cumulative rainfall at their rainfall stations for August to date is:
- Newlands 172.7mm (long term average: 243.6mm);
- Wynberg 140.2mm (192.9mm);
- Steenbras 85.3mm (123.2mm);
- Table Mountain 163.6mm (213.5mm);
- Theewaterskloof 66.9mm (76.7mm) and
- Wemmershoek 117.7mm (154mm).