South Africa has even less water than previously thought, a study has found. Scientists have warned that the country, with 98 percent of its surface water allocated for use, faces tough decisions as it becomes hotter and drier.

But the Water Resources of South Africa 2005 study, the fifth of its kind, found 4 percent less surface water than had been estimated in 1995.

“With each of the national water studies carried out since the 1950s, our estimate of the country’s total natural water resources has declined,” project director Brian Middleton said. “If we were allocating water according to the higher estimates made in previous studies, we would find that there is simply not enough water to meet our needs.”

The study, completed late last year, with its findings now being released, was commissioned in 2004 by South Africa’s Water Research Commission (WRC) “after significant consultation in the water industry”.

It was carried out by a consortium of scientific and engineering consulting firms, producing a detailed survey of surface and groundwater and water quality.

Middleton said the findings were intended as a planning tool for a wide range of users, including developers, farmers, policy-makers and municipalities. It provided localised information that would be useful, for example, for showing how much water was available and how wastewater would affect water quality.

What made the new data particularly valuable was that it integrated surface and groundwater information, Middleton said.

The study found that about 10 000 million cubic metres of groundwater was available for use every year, but that this would be 25 percent less during droughts.

Nearly 50 000 million cubic metres of surface water was available yearly.

Another study, reported in the SA Journal of Science this year, found that while 98 percent of surface water was allocated for use, 41 percent of the usable groundwater was also allocated. Also, the country had become 2 percent hotter and 6 percent drier since the 1970s and this would affect food security and hit poor people hardest.

craig.mckune@inl.co.za

* This article was originally published on page 5 of The Cape Times on September 28, 2009