Cities across the world have grown, thrived and expanded along rich, perennial sources of water, be it lakes, rivers, springs or even seas. So, where did all the water go?
While the world’s most dramatic urban crisis unfolds in Africa, recent studies say at least 200 cities across the world are fast running out of water. An analysis by Down To Earth shows 10 of them are headed towards Day Zero—when the taps will run dry (see map ‘Global sinks’). This comes as a surprise because cities across the world have grown, thrived and expanded along rich, perennial sources of water, be it lakes, rivers, springs or even seas. So, where did all the water go?
Robert McDonald, lead scientist at the US-based environmental group Nature Conservancy offers an explanation. “The main long-term driver of these shortages is the unprecedented urban growth occurring around the world,” he says. Rightly so. There has been a massive redistribution of populations in recent decades. Urban areas, which account for just 3 per cent of the total landmass, are now home to 54 per cent of the global population today, says a study published in Nature this January. The UN expects this rapid urbanisation will go on at least till the mid of 21st century. By then, urban populations would make up about 66 per cent of the world’s total population. Around 90 percent of this growth is expected to be in developing countries.
“With growth in population come changes in land-use pattern, which can affect water availability in a city,” explains T V Ramachandra, professor of ecological engineering at the Indian Institute of Science (IISc), Bengaluru. For instance, he says, following Bengaluru’s rise as the information technology hub, built-up area of the city has increased from a mere 8 per cent in 1973 to 77 per cent now. A study by Ramachandra and his colleagues at IISc shows that the number of waterbodies like lakes has also reduced in Bengaluru by 79 per cent due to unplanned urbanisation and encroachment. This has severely restricted groundwater recharge. To make matters worse, the Bangalore Development Authority predicts that the city’s population might grow to reach 20.3 million by 2031.
Beijing, the capital city of China, also faces a similar predicament. Though more than 200 rivers and streams can still be found on official maps of this arid city, they have all dried up. For the past three decades the city has survived by digging, boring and drilling for groundwater. Now hydrologists warn that groundwater too is running out. “Groundwater is depleting at a rate of 1 metre per year and becoming polluted,” says Scientist Lixia Wang of the Nanjing Institute of Environmental Sciences under the Ministry of Environmental Protection, Nanjing. Today, only 119 cubic metres of water is available per person per year in Beijing, says Wang. Anything less than 1,000 cubic metres per capita annually is considered “water scarce” by the UN. Overextraction of groundwater has already caused the city to sink up to 11 cm a year, shows a research led by Mi Chen of the College of Resources Environment and Tourism, Capital Normal University, Beijing. Experts say land subsidence can damage infrastructure like roads and bridges and increase the chances of flooding and earthquake.
Half way across the globe, Mexico City’s experience is even more tragic story of urban growth. This largest metropolis in the Western Hemisphere is located in the Valley of Mexico where 700 years ago the Aztecs had built a city of floating gardens, known as “the Venice of the New World”. Over the years, the lakes that once filled the plains have been steadily drained by settlers. The lake beds now remain covered by a grey sea of concrete, tarmac and steel, forcing the city to source its supplies by pumping water from hundreds of metres underground or from a distance of over 100 kilometres. But these projects are taking a toll on the city. While overextraction of groundwater has caused the city’s soft base (heavily saturated clay) to sink at 40 cm per year, transporting billions of litres to the megalopolis at 2,400 metres above the sea level through seismically active mountains is fraught with danger.
Then there are cities like Sanaa of Yemen, which after exploiting the last drops of groundwater are looking for alternative sources. The city is growing at 7 per cent a year. World Bank officials working on water projects in the Sanaa basin say groundwater level in the basin has fallen from 30 metres in the 1970s to around 150 metres in the 1990s. Media reports speculate that the city might reach Day Zero in 2019. To avert the crisis city authorities have started tapping fossil aquifers—deep pockets under rock layers where water has remained stored for millennia. Once tapped there is no way to replenish these aquifers.
But the crises faced by Bengaluru, Beijing, Mexico City and Sanaa are not the making of sprawling urban areas alone. These are among the cities where urban planners have failed miserably to manage their water resources.
Crisis of management
Over the years, Bengaluru has become increasingly dependent on the Cauvery river for drinking water. In fact, in February while delivering a long-awaited verdict on the sharing of the Cauvery water between Karnataka and Tamil Nadu, the Supreme Court allocated around 6.5 thousand million cubic feet of water specifically for Karnataka’s capital Bengaluru. The court said that this was made keeping in mind the “global status of the city” and the demands of its burgeoning population. But analysts say the increased allocation will bring little relief to the city unless it manages the water well. The 2013-14 report of the Comptroller and Auditor General states that half of the Cauvery waters, supplied to Bengaluru between 2009 and 2013, was wasted either due to pilferage or leakage due to antiquated plumbing.
Mexico City also loses 40 per cent of the water due to leakage, aged piping, lack of maintenance and illegal connections. Some estimates show that the lost water, if saved, could provide supply for up to 4 million people every day. Beijing’s water crisis is, however, the culmination short-sighted policies that have promoted overuse of limited water resources since 1949. This policy of guaranteeing water supply to the capital at little or no cost has wreaked havoc on Beijing’s farmers and encouraged wasteful consumption by industrial and urban consumers, says a 2008 report by Probe International, a Canadian public interest research group.
Eric Odada, professor of geology at the University of Nairobi and director of the African Collaborative Centre for Earth System, says lack of water governance is also at the helm of Nairobi’s long-standing crisis. The city is so heavily dependent on surface water that it plunges into a crisis whenever the monsoon plays truant. The water shortage became acute in 2016 because the city had not received adequate rainfall for four consecutive years. But heavy rains in April 2017 had caused severe floods. Ideally, this should have ended the city’s water woes. Instead, people continue to queue up for water in several localities. “This situation would not have arrived had the government harvested the excess floodwater,” says Odada. The other major problem is inadequate water supply network. About 75 per cent of the Nairobians buy water from the kiosks and pushcart vendors at a higher price—up to 300 times the supply rate—because they are either not covered under the city’s water supply system or do not receive adequate supply (see ‘Running out’).
The problems of Istanbul, the most populous city in Turkey, are quite similar to that of Nairobi. In 2014 and 2015, Istanbul faced severe droughts. Water in the reservoir dipped down enormously in 2014 and in January it was just enough for 100 days, show official records. The city authority had to plan for transport of water from other basins. The city got relief in 2016 after a smattering of rain and the reservoirs filled to 85 per cent of the capacity. However, poor planning has again put Istanbul in the list of water scarce cities. The decline in the water table due to unsustainable extraction ranges from 30-150 metres in some areas. By 2020, the demand-supply gap will reach 607 million cubic metres per year, says a study published in the journal Environment, Development and Sustainability in 2015.
Heavy dependence on surface water is also the reason São Paulo, one of the 10 largest metropolitan cities in the world, faces water crisis. The city depends on six reservoirs on the Tietê river and its tributary for water supply. But this also makes it vulnerable to precipitation anomalies. In 2015, the Brazilian city experienced its greatest water crisis in over 80 years after rainfall was below-average for two consecutive years. As the authorities introduced a water rationing system, residents endured 12-hour water cutoffs daily; the licences that authorise businesses, agricultural enterprises and private entities to draw directly from rivers, reservoirs and artesian wells were also suspended. Brazilian scientists, including its water utility officials, claimed that large-scale felling of rainforests in the Amazon basin was a major cause of the drought; rainfall was half in 2014-15 when compared to the previous worst year. While analysts do not ignore the connection, they say it’s time the utilities diversified their water resources and plugged leakages. São Paulo loses almost 30 per cent of its treated supply due to leaks in the piping system.
Is assured supply ENOUGH?
Dearth of water is not always the reason for water stress. In several cities people suffer due to lack of access to sufficient clean or potable water. Consider Karachi. This premier industrial and financial centre of Pakistan is also the country’s most populous city. Media reports say the Karachi Water and Sewerage Board (KWSB) barely meets 50 per cent of the city’s total requirement even as its population grows by 5 per cent per annum. Mahmood Ahmed of the Shahid Javed Burki Institute of Public Policy at NetSol, a non-profit in Lahore, says KWSB is infamous for its irregular and inequitable water supply. Though 60 per cent of the households are covered by KWSB network, all they receive is water at a low pressure and for a few hours. The 12 community points meant for informal settlements, catering to over 50 per cent of the city’s population, barely yield any water and people invariably resort to tanker mafias. The worsening water crisis resulted in civil unrest in the city in June 2016.
But do the ones who receive assured water supply receive clean water? In 2011, the World Wide Fund for Nature (WWF) released a report “Big cities, big water, big challenges”, which says a big No. In Karachi, for instance, only 57 per cent of the households have proper sewerage systems. This means a large amount of raw sewage gets washed away into open drains, contaminating leaky pipes, shallow aquifers and the Lyari and Malir rivers that are the major water sources of the city. A 2007 report of the Asian Development Bank says Karachi dumps around 340 million cubic metres of wastewater into the Arabian Sea every day; the Lyari and Malir get polluted immensely. Small wonder, outbreaks of waterborne diseases are a regular feature in the city.
Buenos Aires, the capital city of Argentina, has no reason to be water stressed. The Argentine city is crisscrossed by the La Plata river and dotted with waterbodies. But unchecked expansion of industrial units, including tanneries, along its shores has now made the river into a receptacle of heavy metal-laced industrial waste. Since the city has the capacity to treat only 5.3 per cent of its untreated sewage, most waterbodies remain choked with waste. Since 1940, the city has turned to groundwater to meet its growing industrial and private consumption demands. But over the years, effluents from industries and domestic sewage have contaminated groundwater. The WWF report says groundwater at several places is no longer potable.
In cities like Kabul, however, conflicts are the reason people do not have access to adequate potable water. Bombings have destroyed a large section of supply networks and treatment facilities in this city, where only 20 per cent of the residents had access to treated water. While internal strife has hit water availability in Kabul, in several other cities, water has also resulted in more conflicts—both internal as well as trans-boundary.
Conflicts in the making?
As Chennai struggles for water, there are instances where farmers from surrounding rural districts have been selling water meant for irrigation to the city to the detriment of neighbouring farmers. Now consider this. A city like Delhi depends on neighbouring Haryana and Uttar Pradesh for water. It gets 60 per cent of its water from Haryana alone. Last summer, the Delhi government approached the prime minister for help after Haryana released less water. The Delhi Jal Board officials said that if this continued the city would face a major crisis.
Such conflicts will become common as more than 27 per cent of cities across the world will have water demands that would exceed the surface-water availability, says a study by Nature Sustainability this January. The study analysed 482 world’s largest cities. Almost 19 per cent of cities, dependent on surface water transfers, have a high potential for conflict between the urban and agricultural sectors, since both sectors cannot obtain their estimated future water demands. McDonald, who is part of the study, says policymakers should make agricultural practices efficient to reduce rural-urban conflicts.
But such conflicts would be just the tip of the iceberg in a changing climate. Are the governments equipped for an unforeseen future?
(This story was first published as part of a cover story in March 16-31 issue of Down to Earth under the headline 'The next 10 to go dry').
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