WATCH: Icebergs hold key to Cape Town’s water crisis, says master mariner
Expert marine salvager Nick Sloane is determined to tow an iceberg to the water-deprived Western Cape. He has conducted extensive research into the plan with a team of scientists, engineers and marine experts, coming to the conclusion that in the next five years it will be possible to bring an iceberg to the province.
Sloane said the project would cost $200 million (R2.78 billion) per iceberg and that he was speaking to external funders as he doesn’t want the cost of the project to burden taxpayers.
Sloane said around 150 million litres of water per day could be captured from the icebergs and pumped into the City of Cape Town as well as Saldanha Bay.
“We’ll capture the natural run-off, which would be about 60 million litres a day and we’ll use machinery to increase that to 150 million litres a day.
“That’s pure water every day for a year at about five to six cents a litre,” he added.
Sloane said icebergs, that take thousands of years to break away from Antarctica, are floating around 320km from the Southern Atlantic Ocean’s Gough Island. The island was home to a weather station controlled by the South African Weather Service.
He said there were 90000 icebergs that have been found in the Southern Ocean with about 70% of them viable. The icebergs were between 85 and 110 million tons, 800 to 1000m in length, 400 to 500m wide and are 210m in draft or 72 storeys high.
Gough Island also represents the start of the Benguela current, which is a cold current helping to keep the icebergs at an optimum temperature, between zero and six degrees.
“We need about 400 tons of pull and that wasn’t available 40 years ago but now it is. With two tugs we’ll capture the iceberg and then transfer them to the super tanker, which is far more stable in the Southern Ocean and has a capacity for long-range endurance, and the thrust of the super tanker with the ocean current is far more fuel and energy efficient than the tugs,” Sloane said.
“If we get anywhere near the Agulhas current we end up going to Australia so we need to avoid Agulhas and we can’t go into Table Bay.
“So the only location we can approach is St Helena Bay so we’ll run aground about 28km offshore at about 1.5km/* and that will be the initial anchoring.”
He said to maintain the temperature of the iceberg and ensure there was not mass evaporation or melting, they intend on putting an anchoring system around it and a geothermal blanketing system with a 3km long 150m deep skirt.
“So it’s 450m2 of geotextile skirt.”
He said temporary pipelines would have to be set up from the harbour to pump the water into feeder pipes.
The idea to use icebergs for water was first explored by a team in the 1970s and 1980s, but was deemed unviable.