Science Matters: Lessons from Cape Town’s water crisis

  • Mar. 14, 2018 2:36 p.m.

Many of us in Canada take water for granted, despite drinking water problems in First Nations communities — the subject of a recent column. World Water Day (March 22) reminds us that as the human population continues to grow, putting greater demand on all resources, and as climate change exacerbates drought in many places, we can’t be complacent.

Our cities may not be running out of water yet, but people in Cape Town didn’t expect their water supply to go dry. The four-million residents of South Africa’s second-largest city could see their taps turned off by May 11, called “Day Zero” — or sooner, if people don’t obey severe water restrictions.

“People didn’t believe anything like this could happen, but I think the reality has dawned on everyone and it is pretty tense,” University of Cape Town hydrologist Piotr Wolski told Smithsonian magazine.

Cape Town is entering its fourth year of drought — the worst in 100 years, with an average of 234 millimetres of rainfall a year for the past three years, less than half the average since 1977. Wolski says climate change is a big part of the problem, but so is city mismanagement.

Cape Town isn’t the only city with these problems. São Paulo, Bangalore, Beijing, Cairo, Jakarta, Moscow, Istanbul, Mexico City, London, Tokyo and Miami all face water shortages related to climate change, population growth, waste and mismanagement. Depleted supply is only one result. As more water is drawn from underground aquifers, land is sinking, disrupting road and transit infrastructure and building foundations. As water for agriculture becomes increasingly scarce, food prices rise, which can lead to conflict and human migration.

Canada has more freshwater per capita than most countries, but not as much as we might think. Although water covers 70 per cent of Earth’s surface, only three per cent is fresh. Canada has about 20 per cent of the world’s freshwater, but only seven per cent of renewable freshwater. (A lot is stored in glaciers, lakes and aquifers that aren’t being replenished, or at least not fast enough to replace usage.) As our agricultural and industrial activity expand and population grows, water demands grow and more sources become polluted.

Cape Town introduced a number of measures to combat its crisis. People are restricted to 50 litres of freshwater a day, going down to 25 after Day Zero — although average consumption is still about 95 litres a day. Europeans average 100 litres a day, and Canadians each used about 250 litres a day in 2013, down from 330 in 2005, not including industrial, commercial and other uses. Consumption has been declining as more people install low-flow shower heads, faucets and toilets.

Cape Town’s government is also trying to diversify its water supply by drilling for groundwater and building desalinization and water recycling plants, and has imposed higher fees on those who use more than a certain limit.

With freshwater shortages looming, it’s wasteful to use drinking water to flush toilets and water lawns. Although recycling or re-using toilet water, or “black water” — about one-third of water use in the average household — is difficult, although not impossible, because of bacterial contamination, grey water from baths, showers, sinks, dishwashers and laundry machines can be treated and used to flush toilets, water plants and gardens, even wash clothes. That can save as much as 70 litres of water a day per person.

It also bewilders me that in Canada, where most people can get clean drinking water from the tap, so many pay more for bottled water than gasoline, which creates more plastic and raises issues around corporations profiting from water supplies.

One lesson from places like Cape Town is that we should start tackling the issue now rather than waiting until it becomes a crisis. We must get better at conserving water, preventing water pollution and protecting natural ecosystems like forests and wetlands that filter and store water while also preventing flooding. Beyond the obvious ways to conserve household water, we should also rethink our obsession with lawns that need constant watering, and discourage luxuries like private swimming pools.

Some say our next major wars could be about water rather than resources like oil. If we in Canada and elsewhere plan properly, that needn’t be the case.

David Suzuki is a scientist, broadcaster, author and co-founder of the David Suzuki Foundation. Written with contributions from David Suzuki Foundation Senior Editor Ian Hanington.

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