THE Western Cape’s water resources face a “triple whammy” because of climate change, with declining rainfall levels, increasing fires and increasing alien vegetation impacting on the province’s water supply.
And predictions are that the province, like other parts of the country, will not meet the water demand by 2025.
This is according to Christine Colvin of the CSIR who took part in a World Water Day panel discussion on water in South Africa. The Department of Water Affairs, the Western Cape provincial government and the City of Cape Town are the hosts at the UN World Water Day programme which ends today at the Cape Town International Convention Centre.
Colvin, a research group leader at the CSIR, said South Africa’s rainfall average was half the global rainfall average at 43 500 million cubic metres.
“This is about 1 000 cubic metres a person a year, which sounds like a lot. At the moment we saw at the end of 2009 it was just short of total surface water yield. About 70 percent of the total run-off is captured in the country’s large dams,” said Colvin.
She said agriculture used up most of South Af- rica’s water supply at 62 percent, followed by urban and domestic users at 27 percent. Mining, industry and power generation took up a smaller chunk at 8 percent, but mostly in Gauteng and Mpumalanga.
On the national rainfall levels, Colvin said the levels had decreased “predominantly” in the Western Cape.
“We have six water management areas where there will be a serious shortage of resources that won’t meet water demand by 2025. Rainfall is decreasing predominantly in the Western Cape,” said Colvin.
She said a recent fire in the Betty’s Bay area highlighted the province’s vulnerability to fires.
“The Western Cape faces a triple whammy, with decreasing rainfall, increasing fire and increasing alien vegetation. The combined effect will change the way catchment yields water for our dams. And the people most vulnerable to this are the poorest of the poor,” said Colvin.
She said the question now was: “How can we increase storage to buffer increasing variability?
“Where can we make more use of ground water particularly in the Western Cape?” asked Colvin.
Dr Deon Nel of the CSIR joined in the discussion saying he thought better use of groundwater should be the future.
“It points to using more groundwater,” he said.
Colvin said there was no way to predict what was happening, but the City of Cape Town was being proactive in its search for alternative water sources like the Table Mountain Group Aquifer.
“We know enough to get going and making an impact,” said Colvin.
In the run-up to the World Water Day conference the city’s utility service executive director, Lungile Dhlamini, told a media briefing that all the challenges would have to be addressed to keep a sustainable water supply.
He said that by 2016, the city’s alternative water resource plans would be taking shape.