31 janvier 2023

Cape Town: Icebergs as a solution to drought

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If Cape Town experiences another Day Zero countdown, icebergs transported from the Antarctic will not prevent it from running out of water. The proposal was made during the 2015–2018 drought, but because to its high cost as well as decreased need and the coming of rain, it was never carried out.

A US scientist has now calculated the 2,500 km travel of a 300 m iceberg from the Southern Ocean to the Mother City, and he claims that by the time it reached, it would have lost just 1% of its capacity, or around 2.4 million liters.

Based on Cape Town's daily usage of 925 million liters of water during the previous week, this amount would only last for less than four minutes.

The iceberg would only be able to provide less than 100,000 people with a day's worth of water if Capetonians were limited to the 25 litres per day that are suggested under 2018 Day Zero plans to shut off the mains water and set up collection sites.

In order to lessen the consequences of wave erosion, the iceberg should be wrapped around the waterline, according to climate modeler Alan Condron of the Massachusetts-based Woods Hole Oceanographic Institution.

When the iceberg arrived, it would have 4.5 billion liters of water, enough to last five days at summer consumption rates or to provide 1.8 million people 25 liters of water apiece.

The iceberg would last three days if all 4.8 million people living in Cape Town were were allowed to consume the 3.2 litres necessary for survival.

As Cape Town's dam levels dropped approaching 20%, the iceberg concept was suggested, but the municipal council felt it would be too expensive at the time. Instead, it put more of an emphasis on lowering usage and constructing emergency desalination facilities.

As the City of Cape Town issues a warning about "a strong signal of a likely, but not verified, drought cycle starting or continuing from the record low rainfall levels between 2015-2017," Condron's article, published in the journal Scientific Reports, revives the theory.



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