Cape Town – It is feasible to try to harvest fresh water from an iceberg for Cape Town's short-term water demands, said Capt. Nick Sloane, an expert in marine salvage, on day two of African Utility Week, held in the Mother City.
"The Cape has had three years of drought and it looks like rainfall this year will take it into a fourth year. This year is not giving us much hope for a wet winter," he warned.
"We need to find alternative solutions, because it is 99% sure that this winter won't be a wetter one than last year. So Day Zero will come back to haunt us in 2019 and maybe even in 2020."
He explained that Cape Town's catchment area needed at least four consecutive years of above-average rainfall to break out of the drought impact on water supply.
"In the meantime, something needs to be done in the short term, between now and next year. In April, the Theewaterskloof dam got 0.2mm rainfall, when it should have [got] much, much more, for instance," he said.
He also explained that rivers in Africa, like the Zambezi and Congo, are too shallow for super tankers to go up to bring bulk water to the Cape. Furthermore, he estimates that such bulk water would cost about five times what Capetonians are currently paying for water.
Water from icebergs, on the other hand, could be delivered at between 2.5c and 3.5c per litre.
About 2 000 billion tonnes of iceberg fracture off Antarctica every year, and about 140 000 icebergs drift around the southern oceans, only to melt eventually.
They naturally drift in South Africa's direction after breaking off Antarctica, and currents take them past, south of Cape Town.
"At any one time there should be about seven large icebergs in our catchment area. We have a team of experts together for this project," said Sloane.
"We will use a bio-textile skirt around the iceberg and use a super tanker to tug it, eventually for it to be moored off St Helena. The ice is pure and will deliver some of the finest quality water available."
About 53% of the world’s fresh water is contained in Antarctica.
"We have potential investors wanting to fund this. All the factors say we can do it. If we can deliver water at 2.5c to 3.5c per litre, then we think it is worth looking at," said Sloane.
"If we do not get rain in Cape Town this winter, we will face Day Zero. Maybe it is time to look at icebergs."
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