World News

Could icebergs be the answer to Cape Town's water crisis?

Posted May 1, 2018 8:50 a.m. EDT

— Cape Town may have narrowly avoided Day Zero -- the date at which the South African coastal city of 4 million people would run completely out of water -- but the extreme water crisis it's facing is far from over.

Draconian water restrictions remain on the city's residents, limiting their water usage to 50 liters a day per person, and if significant winter rains do not replenish the region's reservoirs, the city will once again be faced with prospect of the taps running dry in early 2019.

With desalination efforts proving to be time consuming and costly, unconventional water supply options are being considered as solutions.

One unique idea comes from noted salvage master Nicholas Sloane, who believes it's feasible to harness an iceberg that has broken off from Antarctica and tow it to the coast of Cape Town, where it would melt into usable water.

Sloane, a South African resident, is known for leading the monumental salvage operation of the capsized Italian cruise ship Costa Concordia in 2013.

Antarctica shreds nearly 2,000 billion tons of ice per year and many massive icebergs drift within about 1,200 miles of South Africa.

Sloane told Reuters that a single iceberg, weighing about 70,000 tons, would be enough to provide nearly 150 million liters of water per day for an entire year.

This would meet nearly one-third of Cape Town's water needs, considerably more than desalination and other emergency plans the city is currently pursuing.

But the process wouldn't be an easy one.

The iceberg itself would likely be around a kilometer (0.6 miles) in length and would need to be wrapped in a fabric to limit the amount of melting that would take place on the 3-month journey a trip to Cape Town would require.

The idea is for a large tanker to guide the wrapped iceberg into the Benguela Current, which flows up from the Antarctic Circumpolar Current, along the west coast of South Africa.

Even so, it is estimated that about 30% of the iceberg's mass would melt before it reaches its destination.

Because icebergs have such massive draft, it would likely run aground many miles off the coast, but Sloane and his team have a plan to tether the ice like an oil rig and harvest the meltwater from an opening inside the berg.

Fortunately, the ice is pure water, and would require only very minimal processing before being delivered to Cape Town residents.

This is a significant advantage over other options being considered, such as capturing water from the heavily-polluted Congo river and bringing it to Cape Town in supertankers.

In an interview with CapeTalk radio host John Maytham, Sloane said "the cost [of transporting and treating water from the Congo] does not warrant that kind of action," adding that it may only be good for gray water even after treatment.

Harvesting water from icebergs is not a new idea -- it was first floated in academic circles in the 1970s.

A company in the United Arab Emirates is also planning on towing Antarctic icebergs more than 5,700 miles (9,200 km) through the Indian Ocean to the coast of the UAE to help alleviate the water needs of the desert nation.

But the major engineering hurdles and large costs have so far prevented the idea from taking shape.

There are also some environmental concerns.

A review of the idea in a 2001 special report from the International Water Resources Association found that "melting iceberg material in near-shore coastal waters could cause a dramatic decline in local water temperatures with probable associated adverse effects on sensitive marine organisms."

But Sloane and his team feel they can succeed in the venture and he plans to hold a conference later this month to try to sell the $130 million project to city officials and investors.