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Cape Town awaits Day Zero when its water taps will be turned off

Drought in the Western Cape (StormSignal)Drought in the Western Cape (StormSignal)On 16th April 2018, engineers will turn off water for a million homes and businesses in Cape Town, South Africa, an event that is being called “Day Zero”. It will be the first major city in the world to take this course of action. The crisis has been caused by a severe three-year drought, which has seen water levels in the city's reservoirs plummet to dangerously low levels. After a period of water saving measures, the city's authorities are now preparing for emergency rationing. In place of piped water, they will establish 200 water collection points, positioned around the city to ensure a supply of 25 litres per person per day within 200 metres of every citizen’s home. Questions remain about the city’s 800 schools and the risks to sanitation if their toilets are unable to flush. The authorities insist the schools will remain open.

Western Cape government urges conservation (Discott)Western Cape government urges conservation (Discott)Even there were no rain between now and April, Day Zero could still be avoided—although the city’s authorities now consider it to be “inevitable”. A lowering of pipe pressure and a public information campaign to conserve water have already cut Cape Town’s daily water consumption from 1200 million litres to 540 million litres. If this could be reduced by another 25%, the authorities say, the piped water supply could stay open until the start of the rainy season in May. Consumption would then be down to 50 litres per person per day, which is less than a third of the average daily water use in Britain, for example. But with only around a half of Cape Town’s residents achieving this goal, mayor Patricia de Lille announced that the city has now reached the “point of no return”. With everyone forced into Day Zero, no one will have more than 25 litres a day—an amount less than that typically used in four minutes of showering.

The shrinking Theewaterskloof Dam 2014–18 (NASA)The shrinking Theewaterskloof Dam 2014–18 (NASA)
Day Zero represents the point when water in Cape Town’s six-dam reservoir system falls to 13.5% of capacity—the emergency level. Theewaterskloof Dam, the main water source for the city of Cape Town, has been sucked almost dry of water (see animation, right). One side of the lake is now described as desert: a landscape of sand dunes, cracked earth and dead trees, ringed by the carcasses of stranded fish.


Some blame the vineyards in the surrounding region, because they use a great deal of water, yet have continued to expand during the drought. Others point out that the authorities have been slow to react to the situation and make available badly needed new supplies of water. New water wells have been drilled, and a plant that would reuse waste water is being built. But most of these projects are behind schedule.

Declining water storage levels, Western Cape (Discott)Declining water storage levels, Western Cape (Discott)The drought in the Western Cape province of South Africa began in 2015. Water is supplied chiefly from six major dams in mountainous areas close to the city. The dams are refilled by rain falling in their catchment areas, mostly during the normally wet winter months of May to August. But 2015–17 has been the driest three-year period since records began in 1933.

Scientists have calculated that drought of such severity would be expected to take place only once every 384 years. At the same time, Cape Town’s population has grown massively in the past 20 years—from 2.4 million residents in 1995 to 4.3 million today—while dam water storage has only increased by 15% in the same period.

Dry reservoir, northern Brazil 2015 (Agência Brasil)Dry reservoir, northern Brazil 2015 (Agência Brasil)
Droughts in recent years have caused famine in East Africa. But water crises are now threatening some of the world’s largest cities. Already, many of Mexico City’s 21 million residents have running water for only part of the day. Reservoirs in São Paulo, Brazil, dropped so low in 2015 that the flow of water to taps in many homes was cut to just a few hours twice a week. Only last-minute rains prevented the taps from being turned off completely.

Competition for water in the 21st century is increasing rapidly as population growth drives up demand for drinking water and irrigation. The infrastructure—dams, reservoirs, pipes and sewage systems—is often inadequate in many countries. Meanwhile, climate change is causing greater unpredictability in the weather, with more more extreme storms and longer periods of drought.


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