Cape Town may become the first large city in the world to completely run out of water

The dried up Theewaterskloof dam in Viliersdorp, South Africa. The single biggest dam supplying water to the metropole of Cape Town. [Source : Jon Kerrin]


Cape Town's drought and associated water restriction has officially gone up to the level of a disaster. The news of the drought crisis has spread across the globe, and the world is now paying attention to know the fate of the city. This drought has been caused by three years of very low rainfall, associated with increasing consumption by a growing population.

“Day Zero”, currently forecast for April 16, is the day when the taps will run dry in Cape Town. According to the latest data, dam levels for Cape Town are 26.3% as at January 29, 2018. The day has been approaching faster– brought forward by the city's excessive consumption despite proactive measures like the implementation of water restrictions.

The four million inhabitants will be forced to collect a daily water ration of only 25 litres from 200 water collection points – barely enough for a two-minute shower.


How did this happen?

It has been a slow-motion crisis, triggered by three factors:

• A rapidly changing climate
• The worse drought in more than a century which has pushed Cape Town's water scarcity into a potentially deadly horizon
• Increasing population growth
  
  

Rainfall data visualisations show that 2017 was one of the driest years in recent decades due to the two-previous successive dry winters. Normally, El Nino events bring drought to South Africa while La Nina events bring wet conditions. However, the relationship between these events and the western Cape's winter rainfall is somewhat unsettled. The well-below-average rainfall of 2016 and 2017 occurred during a weak La Nina and a weak El Nino respectively, which does not reflect the expected El-Nino-rainfall relationship.


Some studies suggest that the possibility of extreme drought is increasing in the western part of South Africa. Future climate projections show a possible shift towards a drier, more drought-prone climate. This means that it is possible that man-made influenced climate change has contributed to the severity of the current drought, and even though it is an extremely rare event, similar droughts may not be rare in the future. On a positive note, there will still be wet years, but likely not as many.


What solutions are being implemented?

• Seven new water projects are in preparation to increase supplies: four small desalination plants to make sea water drinkable; two projects to extract water from aquifers; and one project that uses treated effluent. These projects could add anything between 150 and 250 million litres per day to the water supply. They are ambitious projects and they are being implemented in a race against time. It is expected that the first of these projects – extractions from aquifers – will be operational by the end of February 2018
  
  
• Day Zero has already arrived for many farmers in the Western Cape. By the end of January, farmers who are drawing from the Western Cape Water Supply System (WCWSS) will have reached the target usage of 58 million cubic metres and their taps will be closed. The agriculture sector uses approximately 47% of the WCWSS compared with 48% used by the city of Cape Town. This means that from February onwards there should be more water available for supplying Cape Town itself.

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©2018 Oceanographer Daneeja Mawren