Wed, Jul 04, 2018 - Page 6 News List

Tow-an-iceberg plan may ease Cape Town drought

AFP, CAPE TOWN

Sloane Marine founder Nick Sloane makes a presentation at the African Utility Week conference on May 16 in Cape Town, South Africa, showing how an iceberg might be towed to Cape Town to alleviate the drought affecting the region.

Photo: AFP

It is a plan as crazy as the situation is desperate — towing an iceberg from Antarctica to Cape Town to supply fresh water to a city in the grip of drought.

Earlier this year, Cape Town came within weeks of shutting off all its taps and forcing residents to line up for water rations at public standpipes.

The cutoff was narrowly averted as people scrambled to reduce their water usage and autumn rains saved the day, but the threat is expected to return to the coastal South African city again next year and beyond.

“The idea sounds crazy,” said maverick salvage expert Nick Sloane, the brains behind the tow-an-iceberg scheme. “But if you look at the fine details, it is not so crazy.”

Sloane suggests wrapping the iceberg in a textile insulation skirt to stop it melting and using a supertanker and two tugboats to drag it 2,000km toward Cape Town using prevailing ocean currents.

The iceberg, carefully selected by drones and radiography scans, would be about 1km in length, 500m across and up to 250m deep, with a flat, tabletop surface.

Melted water could be gathered each day using collection channels and a milling machine to create ice slurry — producing 150 million liters of usable water every day for a year.

Sloane’s idea might be dismissed as mere fantasy.

However, the 56-year-old Zambian-South African has a reputation for taking on the impossible after he refloated the giant Costa Concordia cruise ship that capsized in 2012 off the Tuscan island of Giglio, killing 32 people — one of the world’s largest and most complex maritime salvage operations.

“Icebergs are made of the purest freshwater on Earth,” the founder of Sloane Marine said.

“Thousands break off every year. Mother Nature has been teasing mankind with this for a long time, saying ‘this is here,’” he said.

He estimates it would cost US$100 million to haul an iceberg on a journey that could take up to three months, and another US$50 million to US$60 million to harvest the water for one year as it melts.

“In Russia, they have pushed [icebergs] away from oil installations — but small ones, they are about half-a-million tonnes. [Here] we are talking about 100 million tonnes,” Sloane said.

To tackle the drought, Cape Town has enacted measures ranging from building seawater desalination plants to issuing strict instructions to only flush toilets when necessary.

Whether Cape Town authorities will be persuaded to embrace the iceberg project is unclear.

“At this stage it appears to us that in fact the groundwater or desalination options are cheaper or at least equal cost price,” Cape Town Deputy Mayor Ian Neilson said.

There are also questions on how the water from the iceberg will be channeled into the city’s distribution system.

Another problem is that there is no guarantee that by the time the iceberg is hauled to Cape Town, it will still be able to produce the promised volumes of water.

Sloane’s plan is to tow the giant iceberg about 150km further north to South Africa’s St Helena Bay, where the cold Benguela Current keeps water at about 0°C.

Once there, the iceberg could be anchored in an old submarine channel, Sloane said.

As the iceberg melts, water will be collected each day, pumped into tankers and driven to Cape Town.

“It won’t sort out Cape Town’s crisis, [but] it will be about 20 to 30 percent of their annual needs,” Sloane said.

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