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Don Paul: A looming water crisis as Cape Town prepares to turn off the taps

Few times have a modern, major city been in water trouble the way Cape Town, South Africa, is in trouble. “Day Zero” is May 11. That’s the day government officials expect to turn off tap water to the more than 4 million residents of the city.

The date May 11 is actually a bit of good news, because earlier estimates had centered on mid-April. However, area fruit growers and farms have already used up their allotment of water for the season and are no longer draining regional reservoirs.

In a National Geographic article, correspondent Craig Welch reports that attempts to curb urban water use as the crisis loomed have failed. That failure leaves officials with the stark choice of turning off the taps and forcing the population to go to water stations to receive their allotment in tight rationing measures. The rationing will be strict to the extent that armed guards will surround the water collection lines. This draconian measure is seen as better than allowing taps to run dry and for the city to simply run out of potable water.

How did Cape Town get into this crisis? A record drought has been going on for three years. In early 2014, the city’s six reservoirs were at capacity. By last month, the reservoirs were down to 26 percent and receding fast. The plan is to turn off the taps when reservoir levels drop to 13.5 percent, now estimated to happen around May 11. The hoped-for rainy season, which has failed for three years, would arrive for May-June.

It’s not as if there has been no cooperation during this drought from the populace and businesses. Fees for water were increased, leaks were fixed, and there was a limited drop in usage. However, population growth and vertical urban sprawl toward the base of famous Table Mountain exacerbated the effects of the drought.

Table Mountain is the moisture-grabber for the region. Most of South Africa is arid or semi-arid. Table Mountain captures moist winds from the sea, forcing condensation and the development of precipitation as the moist winds ascend up the windward slope to cooler temperatures. This is typical of many mountain ranges.

City officials made the high-risk assumption that precipitation patterns would continue as per normal climatology in allowing the city to grow, despite climate modeling that projected more frequent dry spells and less reliability of seasonal rainfall. Arguing whether or not this drought is tied to climate change or natural variability is fruitless at this stage of the game for the immediate crisis. For future planning, officials are now aware the reliability of their water supply is greatly reduced. This has been the worst drought in more than a century. Eventually there will be relief, but scientists – including hydrologists, engineers and climate experts – have made it clear events like this will be more likely in the future than they have been in the past.

National Geographic reports other great cities under great water duress. Large numbers of Mexico City’s 21 million people get running water only part of the day. Jakarta, Indonesia, is sucking up ground water so fast the rate of geological sinking in the region is outpacing the rate of rising sea level, a very dangerous synergy. Sao Paulo, Brazil’s most populous city, was down to 20 percent reservoir capacity in 2015. Water pipes began sucking in mud, and water trucks that were deployed were looted. The flow to taps was cut to just a few hours, twice a week. Last-minute rains prevented a total shutdown, as Cape Town currently faces. If and when Day Zero arrives there, residents will have to get by on 25 liters of water per day, the amount of water used in a 4-minute shower. The 25 liters would have to supply far more uses than just a shower, so it will be stretched very thin per person. That amount would be further reduced if the drought doesn’t break.

Along with water shortages in urban centers, millions of people in rural areas like Somalia and the other nations surrounding the Arabian Sea are already suffering the effects of water shortage and deprivation. Recent major technological progress by Israeli engineers in desalinization efficiency and lowered costs may be the best hope for some of these areas.

For Cape Town, there will need to be more efficient use of a network of underground tunnels that allow wasted potable water to flow back out to sea, along with sewage. Underground storage of water sharply reduces losses to evaporation. About the only positive thing to be said for this crisis: It is an awakening.

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