“Icebergs are made of the purest freshwater on earth,” Nick Sloane, the founder of Sloane Marine Ltd says, reflecting upon possible ways to save Cape Town from drought. “Thousands break off every year. Mother Nature has been teasing mankind with this for a long time, saying ‘this is here’.”
Nick Sloane estimates it would cost $100 million (S$137.3 million) to tow an iceberg to Cape Town that could take up to three months, and another US$50-60 million to harvest the water for one year as it melts.
In Russia, they have pushed icebergs away from oil installations, Sloane continues to explain his plan, pointing at existing experience. However Russian engineers managed to push away only small icebergs of half-a-million tons. But Cape Town challenge requires a 100 million tons of ice to quench residents thrust.
Dr Chris von Holdt from Aurecon advisory practice, who has done a technical assessment and economic evaluation of the iceberg proposal, said: “I believe it has sufficient technical feasibility and economic merit to be considered seriously as a supply option for filling the supply gaps during periods of drought.”
Dr Olav Orheim, a former director or the Norwegian Polar Institute has analysed 271 000 icebergs, of which only 7% would be suitable, because the shape must be tabular, with a flat top and steep sides, and a thickness of 200m to 250m.
Once a suitable iceberg has been assessed, it will be “hacked”.
Two tugs will encircle the iceberg, pulling an enormous piece of geotextile material around it as a “skirt” that reaches down the sides of the iceberg beneath the sea.
A third tug stands by as back up. A tanker will then tow the iceberg, with the distance between the tanker and the iceberg about 1.5 km.
The two tugs will steam alongside, ensuring the iceberg stays on its course to Cape Columbine north of Saldanha Bay.
For reasons of the severe drought, the iceberg cannot go close inshore but will “anchor” itself on the seabed about 40 km offshore.
It will then be moored using a system similar to that used by certain offshore oil rigs.
In a way it will resemble one of the giant installations of artists Christo and Jean-Claude wrapped in fabric.