Water experts will tell you that in stressed areas like California, there are still many opportunities to squeeze more efficiencies and make do even in times of severe scarcity. We’ll need every hack to deal with what’s coming.
June 26 is the day the largest city in North America may run out of water. There’s a race to find solutions.
In Mexico City, more and more residents are watching their taps go dry for hours a day. Even when water does flow, it often comes out dark brown and smells noxious. A former political leader is asking the public to “prioritize essential actions for survival” as the city’s key reservoirs run dry. Meanwhile, 2,000 miles south in the Colombian capital of Bogotá, reservoir levels are falling just as fast, and the city government has implemented rotating water shutoffs. The mayor has begged families to shower together and leave the city on weekends to cut down on water usage.
In warning about the potential for a Day Zero in the water system, both cities are referencing the famous example set by Cape Town, South Africa, which made global headlines in 2018 when it almost ran out of water. The city was months away from a total collapse of its reservoir system when it mounted an unprecedented public awareness campaign and rolled out strict fees on water consumption. These measures succeeded in pulling the city back from the brink.
Six years later, Cape Town stands as a success story in municipal crisis management, but experts say its playbook will be hard for Mexico City and Bogotá to replicate. Instead of focusing primarily on changing public behavior, these cities will need to make big investments to improve aging infrastructure and shore up their water supplies. How they fare in these endeavors will in turn inform future efforts to make the world’s fast-growing cities resilient to increasing climate volatility.
“The bigger question, and what’s relevant for other cities, is now that we’ve experienced this, what can we do going forward to make sure that this doesn’t happen again?” said Johanna Brühl, a water expert at the nonprofit Environment for Development in South Africa who has studied Cape Town’s water crisis.
Coining the very phrase “Day Zero” was part of Cape Town’s solution to a water crisis that many officials had seen coming for years. As reservoir levels fell between 2015 and 2017 amid a drought, city leaders released dozens of statements urging residents to reduce water usage, but no one paid much attention. Only in early 2018, when officials started talking in increasingly apocalyptic terms about a collapse of the municipal water system, did residents — and international media outlets — start to pay attention.
The city rolled out a set of measures to enforce cuts, including a tariff system that charged more thirsty users a higher price per gallon plus a door-knocking campaign to shame the biggest water hogs. But it was the rhetoric around Day Zero that seemed to be the most effective tool to slash water usage, experts who studied the crisis told Grist. When the local government warned that residents would have to pick up buckets of water from public collection points managed by the military, consumption plummeted. The effort to stave off a water crisis began to look like a grassroots movement, with residents sharing conservation tricks like flushing the toilet with water captured from the shower.
By April 2018, water usage had fallen to about half of what it was three years earlier, a decline that astonished even city officials. As consumption dropped, the city pushed the estimated date of the apocalypse out by a few days, then a few weeks. When a big rain arrived in the early summer and began to refill the reservoirs, the government turned off the countdown altogether, declaring the crisis at a temporary end.
Cape Town’s communications of the drought were successful due to the city administration’s ability to accurately measure its daily drinking water production, as well as its dam levels. This enabled the city to set a target water usage for each resident per day, so that the reservoirs in the dams could last until the winter rainfall season.
Daily public communication stressed the need for residents to, inter alia, take short showers, flush only when necessary, and refrain from using drinking water for gardening. Campaigns also targeted visitors to the city, under the slogan “save (water) like a local.” The city communicated a moving forecast of whether “day zero” was being pushed out as a result of successful water saving measures.
In addition to raising awareness, the city also looked to increase distribution efficiency and curb water losses. Recent studies have shown that pressure management in urban water distribution networks is one of the cost-effective ways to extend asset-life and reduce water leakages, which can sometimes account for up to 70 percent of total water losses. Cape Town is fortunate to be a leading metro for pressure management technology, establishing 170 pressure management zones covering 68 percent of the water network as of June 2021. This upped the city’s ability to reduce leaks, bursts, and especially consumption, with savings of 70 million liters per day (ML/d) at the peak of the 2018 drought.
The clue is the phrase “largest city”.