In April 2018, the City of Cape Town, South Africa came within days of running out of water. Three million people faced the prospect of faucets running dry, civil unrest, and an unprecedented water-resource crisis that threatened to change the face of the city forever. Two years on, we consider how Cape Town avoided “Day Zero” and how the solution to preventing such a disaster might come from the ocean.
The once-in-a-century drought of 2015-2018 has had unprecedented consequences on the residents of Cape Town. Following a collective drive to halve water consumption within two years, debilitating water restrictions, and a change in how we treat this precious resource, the city at the end of Africa managed to stave off the drought.
Images of dams at 10% capacity kept the world focused on the situation and a series of innovative, if desperate, measures were put in place to manage the dwindling water supply. The government drilled into local underground aquifers, tapping into million-year-old reserves, per person water rations of 50 liters (13 gallons) per day were instituted and non-essential taps were locked shut.
Whilst these measures fought off what seemed an inevitable disaster, authorities are now looking into alternative solutions should the rain stop falling again. Many have turned to the oceans for their salvation.
Part of the emergency measures put in place included the speedy installation of three small but temporary desalination plants along Cape Town’s coastline. This is proving a quick fix, however as the prohibitively expensive process of turning seawater into potable H2O is not a sustainable one.
A radical idea, floated in mid-2018 and initially scoffed at as fantastical, is now being seriously considered. Towing an iceberg from Antarctic Seas (1400 miles away) to within 15 miles of the African shoreline could help to solve the city’s drought dilemma. Marine engineers have proposed that “capturing” a 1600-foot-wide, 800-foot-high, flat-topped iceberg off of Antarctica and towing it back to warmer climes may be the answer. Wrapped in a massive insulating skirt to prevent melt during the 3-month journey, the ‘berg would then be “mined” for fresh water.
Another proposal looks at taking advantage of a massive freshwater reservoir at the bottom of the ocean off the southern tip of the African continent. The Bredasdorp Basin, an 18 000-square-mile region of ocean floor 105 miles from Cape Town is purported to hold massive amounts of fresh water, separated from the salty seawater by layers of clay, locked beneath the tides. Getting to it, however, may be a challenge. Researchers must first determine if the supply is a leftover reserve that was deposited by a freshwater glacier during the ice ages – a time when sea levels were hundreds of feet lower than they are today – or if the water is collected from land-based runoff. If the latter, this could prove an exciting renewable resource.
One thing is clear – whatever the eventual solution, if we turn to the seas to sate our thirst for fresh water, they need to be clean. Already reports of sewage emanating from passing ships and the city itself of tainting desalination plants are emerging. Whilst authorities were busy seeking answers to the drought, they neglected the impact that we’re having on the surrounding waters. Facing this new problem, plans are being installed to filter and manage sewage runoff from the land. The ships, however, are not subject to, nor do they adhere to, the lax regulations in place governing what they leave behind as they round the Cape of Good Hope.
In order to solve the bigger problems, we must first get through the smaller ones. Technologies have now been made available that allow ships to retain their waste on board in a safe, efficient manner. From the byproducts of their mechanical operations to the human-generated waste collected onboard, these technologies are allowing vessels to make port and dispose of their unwanted excess in an eco-friendly manner - without ever poisoning the oceans. It is up to us to make sure that we use them.