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Poor planning to worsen climate impact on S. Africa's water supply

Thu, 10 Mar 2011 18:13 GMT

Source: alertnet // Jocelyn Newmarch

A man walks across a flooded bridge, 60 km (37 miles) south of Durban in South Africa, June 18, 2008, after heavy rains caused flooding. REUTERS/Rogan Ward

JOHANNESBURG (AlertNet) - Weak infrastructure management and poor planning will exacerbate the serious effects of climate change on South Africa’s water supply, local experts have warned.

“We are very good at burglar proofing, bullet proofing, but are we good at climate proofing?” Roland Schulze, professor in hydrology at the University of KwaZulu-Natal, asked last month’s South African Water and Energy Forum.

Earlier this year, floods on the Vaal river system, described as a once-in-15-years event, had devastating consequences. The floods have highlighted South Africa’s vulnerability to climate change, which is expected to change rainfall patterns.

“We already live in a high-risk climate with many uncertainties,” Schulze said, adding that climate change will add another layer of stress.

Mean annual temperatures in South Africa are expected to increase by 2 to 3 degrees Celsius by 2050, and by 5 to 6 degrees by 2090, “if the scenarios play out the way we expect”, Schulze cautioned.

South Africa’s rainfall variability is exceptionally high by international standards, matched only by Australia’s. Run-off is even more volatile: for every unit of rainfall change, the corresponding shift in runoff is up to 2.5 times higher, Schulze said.

In addition, South Africa has practical problems in managing water, such as treating sewage, and is losing water management skills. Water catchment areas are now supposed to be managed by groups of users, but only a few of these forums have been established.

MORE VARIABLE CLIMATE

In future, South Africa’s climate variability is expected to intensify. Evaporation is expected to increase by between 5 and 10 percent by 2050, meaning that an additional 1,000 cubic metres of water could be released into the atmosphere per primary river system, or catchment, with that amount doubling by 2090. “These are significant losses,” Schulze said.

The Lesotho Highlands Water Project - which provides much of the water consumed by South Africa’s richest province, Gauteng - is located in an ecologically sensitive area, and could see run-off decrease by a quarter due to rising temperatures, bringing serious consequences for the country’s water supply.

South Africa - which hosts U.N. climate talks at the end of this year - is also likely to face a different drought pattern. It may see fewer meteorological droughts, when rainfall is lower than the average, but more “hydrological” droughts, which occur when the amount of water in river systems is below normal levels.

The country will also need to manage more frequent floods and flash floods, as well as rising sea levels and storm surges.

“Adaptation is not going to be easy. Climate change has to be part of integrated thinking,” Schulze said.

TOO FOCUSED ON CLIMATE CHANGE?

But some experts believe analysis of water problems focuses too much on climate change. It is often used as a scapegoat, according to Richard Holden of the Trans Caledon Tunnel Authority, which manages the water transferred between Lesotho and South Africa.

“It’s easy to blame climate change, but we don’t look at ourselves and ask, what were we doing to improve the catchment? We need to separate climate change from what we are doing ourselves,” he said.

The Jukskei River in Gauteng is flooding more regularly, for example, but this is due to poorly conceived residential development rather than climate change, Holden said.

Theo de Jager of farmers’ group AgriSA warned that water for agriculture is becoming “less and less useable” as quality deteriorates.

He said only a quarter of South Africa’s staple food crops – maize and wheat – are irrigated, with the rest being rain-fed. Farmers are refusing to irrigate as water and energy costs rise.

“In a dry year, that 25 percent pulls us through. But in the last two years, we’ve had very good rain and produced surpluses. We’re in an awkward position to negotiate anything,” de Jager said. “Only when there’s a drought will we realise the implications for food security.”

PLANNING AT FAULT

Climate change is just one stress factor among many facing communities, including fire and violence, said Wits University climatologist Coleen Vogel. Poor infrastructure management often exacerbates climate-related disasters. In many cases homes are built close together, making it difficult for emergency vehicles to access disaster-hit areas, for example.

Johannesburg’s rainfall distribution may already have started to change, with more heavy precipitation events, Vogel said. Preliminary research has found that since 1960, the number of storms has decreased, but total average rainfall is more or less the same, with the average volume per storm increasing slightly.

“It’s the same pattern we’ve always known, but the impact, or imprint, is stronger,” she said, adding that this is a major issue for planners when designing infrastructure.

In the Western Cape, provincial departments, state-owned companies and agricultural businesses have spent the equivalent of several hundred million dollars repairing the damage from severe weather events in the past decade.

Vogel said money should be used proactively to reduce the impact of disasters, rather than to mop up afterwards.

Jocelyn Newmarch is a freelance reporter specialising in environmental economics, based in Johannesburg.