The Ancient Mariner’s complaint about non-potable water is the most quoted part of his gruelling Rime. But under certain conditions, with the right technology, the sea does become drinkable.

And not just via desalination plants, which are extremely costly (in more ways than one). Mountainous coastal weather events – specifically, moving fog and cloud – can be ‘passed through’ specially designed and strategically placed nets. Droplets then trickle down the mesh into troughs, and into storage vessels. Implementing this system should at least be explored in the city of Cape Town, South Africa, which is currently experiencing a severe drought. But despite the instructive, timeless reliance on condensation as a source of fresh water by diverse plants, animals and humans worldwide, as well as positive scientific experimentation with means of harvesting over the last 100 years, fog seems to have been given the cold shoulder in the great Capetonian drought debate. This is particularly short-sighted considering the recent, significant improvements in fog net design – notably by Munich-based Peter Trautwein, whose CloudFisher model markedly improves moisture yields with stabilized mesh, and provides resistance to overall structural damage by gale force winds.

Dry Run

2017 was a very dry year in Cape Town. Although 2018’s winter to date has been more traditionally rainy, residents are still limited to 50 litres daily, to ward off the dreaded Day Zero, when taps stop running and long queues for doled-out water start to form. In light of this, ædi’s position is that it is irresponsible not to test whether the CloudFisher’s success in Tanzania, and Morocco’s arid Anti-Atlas region, can be repeated on Table Mountain: Hoerikwaggo, ‘Mountain in the Sea’ to the earliest Khoi inhabitants; now hemmed in by 4 million urbanites (and even thirstier farms beyond). And so frequently, in summer, topped with a cloth of cloud forever sliding towards town. Actually, Table Mountain’s micro-climate tends to contain lots more moisture than the rest of the peninsula all year round. In fact, at the peak of the panic over water restrictions in late-2017, Capetonians were stunned to hear that the five mountain reservoirs were ‘full’. The explanation surfaced like this: it often rains on the mountain and nowhere else in Cape Town, and the ‘city dams’ are far smaller than those further away, such as Theewaterskloof, so today they supply only a tiny volume of water to a few residential areas. Maybe so. But surely if, after a year of thorough feasibility-testing within Table Mountain’s various fog and cloud conditions, CloudFisher nets showed promise, the existing reservoir and piping network up there could be dovetailed to the city’s advantage, rather than deemed an obstacle to water harvesting!

Uplifting Fog

To be fair, there has been a reduction of the misinformation, lethargy, bureaucratic bungling and political footballing so prevalent a year or two ago. Almost everyone – officials and members of the public alike – has been forced to wise up and not take water for granted. Even tourists are allowed to learn about the drought in Cape Town now, if they haven’t already taught themselves. It undoubtedly puts some visitors off, however others enjoy the city anyway, and do their bit to use water as sparingly as possible.

Of course, there are still sociopaths and denialists, but anthropogenic climate change is real. Rainfall at the Cape is waning, whereas the population, and consequent need for water, is booming.

A transparent, sustainable, multifarious strategy is apt, and could include: more ingenious, economical irrigation of farms; increased water recycling; non-gung-ho aquifer drilling; the removal of absurdly draining alien vegetation from catchment areas; sensible desalination; and continued concentration on conservative-yet-creative residential and industrial water use. No single measure is going to solve the problem. But that’s no reason to spurn fishing for fresh water on cloudy, wet, windy Table Mountain.