Johannesburg — SA WILL need to consider water supply and demand in planning infrastructure needs, a report released by the Water Resources Group last month says.

The report shows that water demand will outstrip supply by 17,7% in SA in 2030. Better options, the authors suggest, might be found in renewable technologies such as solar, wind, and hydropower that reduce consumptive water use, contributing to the sustainable management of water resources.

The true gap could be much greater, as unexpectedly high economic growth could almost double this amount, and the effect of climate change could also increase the gap.

The group is led by the World Bank and McKinsey, and includes private sector players such as SABMiller , Syngenta, Nestlé and Coca-Cola. The report, Charting our Water Future: Economic Frameworks to Inform Decision- Making, says water decisions need to be considered in the context of the entire economy, rather than restricted to one sector. Four regions received in-depth analysis in the report -- SA, China, India and São Paulo in Brazil.

Industrial demand for water is expected to grow from 1,5- billion cubic metres to 3,3-billion cubic metres in 2030. By then, power generation will account for 12 % of total demand, mining 18% and manufacturing 70 % (up from about 50 % in 2005).

Meeting the water demand for power generation is one of SA's water challenges, according to the report. Up to 25GW of extra power generation capacity is planned for 2025. For the coming decade additional capacity will come from dry-cooled, coal-fired power plants located where most of the coal beds are, with water transfers likely to be required from other regions, as the local water supply will be insufficient.

The mining sector uses water for processes and for dilution of acid drainage. Coal and gold accounted for 80-million cubic metres and 90-million cubic metres respectively in 2005. While gold will decline in coming years , coal will become the sector's main user at more than 180- million cubic metres in 2030.

So far, the sector has not exceeded the amount of water needed for other uses, so no additional supply has been necessary for the sole purpose of dilution.

While projections are hard to make, it is possible that, as pollution increases, demand for dilution may exceed the amount required for other uses, implying the need for additional supply, the report says.