Cape Town was set to run dry on April 12, 2018, leaving its 3.7 million residents without tap water.
“Day Zero” was narrowly averted through drastic cuts in municipal water consumption and last-minute transfers from the agricultural sector. But the process was painful and inequitable, spurring much controversy.
The city managed to stave off “Day Zero,” but does that mean Cape Town’s water system is resilient?
We think not.
This may well foreshadow trouble beyond Cape Town. Cities across the Northern Hemisphere, including in Canada, are well into another summer season that has already brought record-setting heat, drought and flooding from increased run-off.
Water crises are not just about scarcity
Water scarcity crises are most often a result of mismanagement rather than of absolute declines in physical water supplies.
In Cape Town, lower than average rainfall tipped the scales towards a “crisis,” but the situation was worsened by slow and inadequate governance responses. Setting aside debates around whose responsibility it was to act and when, the bigger issue, in our view, was the persistence of outdated ways of thinking about “uncertainty” in the water system.
Read more: As a water crisis looms in Cape Town, could it happen in Canada?
As the drought worsened in 2016, the City of Cape Town’s water managers remained confident in the system’s ability to withstand the drought. High-level engineers and managers viewed Cape Town’s water system as uniquely positioned to handle severe drought in part because of the vaunted success of their ongoing Water Demand Management strategies.
They weren’t entirely mistaken — demand management has cut overall daily consumption by 50 per cent since 2016. So what went wrong?
Limits to demand management
First, Cape Town’s approach to water management was not well-equipped to deal with growing uncertainty in rainfall patterns — a key challenge facing cities worldwide. Researchers at the University of Cape Town argued recently that the conventional models long used to forecast supply and demand underestimated the probability of failure in the water system.
Second, Cape Town’s water system neared disaster in part because demand management seemed to have reached its limits. Starting late last year, the city imposed a limit on water consumption of 87 litres per person per day. That ceiling thereafter shrunk to 50 litres per person per day.