Cape Town Not Alone: The Eleven World Cities Most Likely to Run Out of Drinking Water

As a result of a 20th-century project to drain nearby swamps, water from the Atlantic Ocean began seeping in to the Biscayne Aquifer, Miami's main source of freshwater. Infographic credit: YouTube (source)

by Gaius Publius

One last follow-up to the Cape Town water crisis story. As you may know, the city of Cape Town, South Africa, is experiencing a severe drought that has reduced the region's dams to 30% or less of capacity (with the last 10% unusable). This has forced the local government to declare a Day Zero, described on the city's website as "the day we may have to queue for water."

At the moment, residents are urged to use no more than 50 liters of water per day — about 13 gallons — for all purposes, including drinking, bathing, flushing the toilet, washing dishes, watering plants and gardens, and so on.

If  Day Zero is reached, the water taps will be shut off by the city and water will be strictly rationed. Residents will have to queue for water with their buckets as water is doled out to them. On Day Zero, the ration will be reduced to 25 liters per day. As of this writing, Day Zero is June 4.

The Canary in a Very Large Coal Mine

I've called this a "canary in the coal mine" for other cities around the world, and indeed, for our species' climate prospects in general.

The BBC News website has a helpful list of eleven cities that are closes to the condition of Cape Town, but not quite there yet. Here's that list; Cape Town is just the tip of the iceberg.

• Heading the list — São Paulo, Brazil:

Brazil's financial capital and one of the 10 most populated cities in the world went through a similar ordeal to Cape Town in 2015, when the main reservoir fell below 4% capacity.

At the height of the crisis, the city of over 21.7 million inhabitants had less than 20 days of water supply and police had to escort water trucks to stop looting.

It is thought a drought that affected south-eastern Brazil between 2014 and 2017 was to blame, but a UN mission to São Paulo was critical of the state authorities "lack of proper planning and investments".

The water crisis was deemed "finished" in 2016, but in January 2017 the main reserves were 15% below expected for the period - putting the city's future water supply once again in doubt.

• Next, the tech-fueled city of Bangalore, India:

Local officials in the southern Indian city have been bamboozled by the growth of new property developments following Bangalore's rise as a technological hub and are struggling to manage the city's water and sewage systems.

To make matters worse, the city's antiquated plumbing needs an urgent upheaval; a report by the national government found that the city loses over half of its drinking water to waste.

Like China, India struggles with water pollution and Bangalore is no different: an in-depth inventory of the city's lakes found that 85% had water that could only be used for irrigation and industrial cooling.

Not a single lake had suitable water for drinking or bathing.

The problem in Bangalore is exacerbated by pollution from human waste; India in general is vastly deficient in toilets and a culture of using them.

• A city that may surprise you, a world capital yet, is next on the list — Beijing, China:

The World Bank classifies water scarcity as when people in a determined location receive less than 1,000 cubic metres of fresh water per person a year.

In 2014, each of the more than 20 million inhabitants of Beijing had only 145 cubic metres.

China is home to almost 20% of the world's population but has only 7% of the world's fresh water.

A Columbia University study estimates that the country's reserves declined 13% between 2000 and 2009.

And there's also a pollution problem. Official figures from 2015 showed that 40% of Beijing's surface water was polluted to the point of not being useful even for agriculture or industrial use.

To put those numbers in perspective, 1000 cubic meters per year is about 725 gallons per day per person. That's the break point for the World Bank's definition of "water scarcity."

In Beijing, 20 million inhabitants have about 100 gallons per day, one seventh of the allotment that defines "scarcity."

• Other cities on the list include Cairo (another world capital); Jakarta in Indonesia; Moscow, Istanbul, London and Tokyo (four more world capitals!) ... and Miami.

Miami's Water Troubles

Despite its large annual rainfall, the American city of Miami is especially vulnerable to drinking water shortages. BBC News again:

The US state of Florida is among the five US states most hit by rain every year. However, there is a crisis brewing in its most famous city, Miami.

An early 20th Century project to drain nearby swamps had an unforeseen result; water from the Atlantic Ocean contaminated the Biscayne Aquifer, the city's main source of fresh water.

Although the problem was detected in the 1930s, seawater still leaks in, especially because the American city has experienced faster rates of sea level rise, with water breaching underground defence barriers installed in recent decades.

Neighbouring cities are already struggling. Hallandale Beach, which is just a few miles north of Miami, had to close six of its eight wells due to saltwater intrusion.

Even without the problem of sea level rise, Miami's water supply is vulnerable to its water table, made of porous limestone.

Jeff Goodell, writing in Rolling Stone (emphasis added):

South Florida has two big problems. The first is its remarkably flat topography. Half the area that surrounds Miami is less than five feet above sea level. Its highest natural elevation, a limestone ridge that runs from Palm Beach to just south of the city, averages a scant 12 feet. With just three feet of sea-level rise, more than a third of southern Florida will vanish; at six feet, more than half will be gone; if the seas rise 12 feet, South Florida will be little more than an isolated archipelago surrounded by abandoned buildings and crumbling overpasses. And the waters won't just come in from the east – because the region is so flat, rising seas will come in nearly as fast from the west too, through the Everglades. [emphasis added]

Limestone, a porous rock, that forms the Miami ridge also forms the floor, the region's water table:

Even worse, South Florida sits above a vast and porous limestone plateau. "Imagine Swiss cheese, and you'll have a pretty good idea what the rock under southern Florida looks like," says Glenn Landers, a senior engineer at the U.S. Army Corps of Engineers. This means water moves around easily – it seeps into yards at high tide, bubbles up on golf courses, flows through underground caverns, corrodes building foundations from below. "Conventional sea walls and barriers are not effective here," says Robert Daoust, an ecologist at ARCADIS, a Dutch firm that specializes in engineering solutions to rising seas. "Protecting the city, if it is possible, will require innovative solutions."

Miami has been working since its founding to stave off salt water intrusion into its freshwater aquifer.

[In] the 1950s, people started noticing their drinking water was getting salty. In South Florida, the drinking-water supply comes from a big lake just below the surface known as the Biscayne aquifer. Engineers examined the situation and determined that the combination of draining the swamps and pumping out the aquifer had changed hydrostatic pressure underground and allowed salt water to move into the aquifer. To stop this, the Army Corps of Engineers and the South Florida Water Management District built dozens of these salinity-­control structures at key points on the canals. When they were closed, salty water wasn't able to flow into the canals. But if there was a big storm and intense flooding, the gates could be opened to allow drainage.

That worked pretty well for a time. The gates were engineered so that, when they were closed, the fresh water was about a foot and a half higher than the salt water. This freshwater "head" (as engineers called it) helped keep pressure in the aquifer and kept the salt water at bay.

But in the 50 years since the structures were built, much has changed. For one thing, nearly 80 percent of the fresh water flowing into the Everglades has been diverted, some of it into industrial-­agriculture operations. At the same time, consumption has skyrocketed: The 5.5 million or so people who now live in South Florida consume more than 3 billion gallons of water every day (including industry and agriculture). Almost all of that is pumped out of the aquifer, drawing it down and allowing more and more salt water to move in. At the same time, the sea level is rising (about nine inches since the canals were first dredged), which also helps push more salt water into the aquifer.

Says Jayantha Obeysekera, the chief modeler for the South Florida Water Management District, "Here, you can see the problem. The water is only 10 inches lower on [the saltwater] side than on the [freshwater] canal [side]. When this structure was built in 1960, it was a foot and a half. We are reaching equilibrium."

The engineering to address these problems is expensive. Installing new pumps on the freshwater side of the control structures cost $70 million each. The full cost of protecting Miami from a three-foot sea level rise will be "upward of $20 billion to $30 billion."

One day that cost will be deemed just too much, and Miami will be abandoned to the world without us — along with most of the other cities on the list above.

You can find more on coming water shortages in world cities at the EcoWatch website. Most of these regional problems, if not all of them, will become severe within the next decade. By most estimates, London, for example, will have to find new water sources by 2025. Trump, or Pence, may still be president by then.

Yes, it's happening now. The last generation kicked the can to this generation. It can't be kicked further.

GP