Wavering water: why round-the-clock urban water supply matters

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Grantham PhD student Simon De Stercke looks at how Mumbai residents cope with just a few hours of running water per day – and why this needs to change, as part of his research on the urban water-energy nexus.

By 2050, two thirds of our planet’s population will live in cities. Creating a blueprint for sustainable cities is therefore the key to unlocking a sustainable future for humanity.

As one of the world’s largest megacities, Mumbai is on the frontline when it comes to sustainable urban development. And like many of its counterparts across the world, providing access to safe, clean water for its 20 million residents, both today and in decades to come, is a major challenge.

While cities are relatively immune to water shortages, a bigger issue is timing. It may surprise you to learn that in almost any area of Mumbai, running water is only supplied for up to a few hours per day.

With links to health, inequality and waste, continuous water supply is one of the foundations of sustainable urban living. It is necessary to achieve the Sustainable Development Goals, which came into effect in January 2016, and will be an important discussion topic at the UN’s upcoming Habitat III conference on housing and sustainable urban development.

Aging infrastructure

Mumbai’s population growth is staggering, with a threefold increase in inhabitants over only four decades. But the city’s water distribution infrastructure has been unable to keep up. As a result, running water is only available for a few hours each day, according to a schedule for each area of the city. During that short window, residents have become accustomed to stockpiling enough water to cover their needs for at least a day.

Local storage methods range from systems of large underground sumps and rooftop tanks for middle and upper class residential blocks, to plastic cans in the slums. With these and various other fixes, Mumbaikars – Mumbai’s residents – cope with the intermittent water supply and effectively convert it into a continuously available resource.

Water system woes

water tanker backs up to a gate from a road
A water truck tops up a building’s underground sump in Colaba, Mumbai (source: Simon de Stercke)

Despite those  fixes, this system comes at a very high social cost for a number of reasons. First, there are many opportunities for pathogens to get into the water in between treatment and consumption, which pose a risk to human health. During distribution, pathogens such as E. coli – which causes diarrhoea – or cholera can contaminate water in unpressurised mains, or while water is sitting in unsafe local storage vessels.

Second, the system furthers and perpetuates the extreme inequality in Mumbai, where almost half the population live in slums while at the same time one family’s private home is a skyscraper. Those at the bottom of the socioeconomic ladder often have to share a piped connection with many neighbours. In this situation, scarcity drives up effective prices to as much as ten times what better-off residents pay for piped water. Treating water immediately before consumption is also more costly than slum-dwellers can typically afford. Thus the poor are disproportionately affected both in terms of quantity and quality of water.

Finally, some argue that city-dwellers without a reliable water supply actually use more water than those with 24 hour availability. Under these uncertain conditions, people tend to store excess water to have a multi-day buffer, but with each supply of new water, the leftover old water is first drained. Some people leave taps open all the time to ‘automatically’ fill their tanks, however without a shut-off mechanism tanks continue to spill over when they are full, thus wasting water that could otherwise benefit the poor.

Popular explanations for these water system woes include corruption, politics and the so-called ‘tanker mafia’. The tanker mafia are undefined entities with interests in the business of bulk water delivery by tanker trucks. These perceptions of social ills in Mumbai’s water system have made it the focus of extensive social scientific research, with poetic titles including: Pipe Politics, Leaky States, Municipal Disconnect and Water Wars in Mumbai. Despite a myriad of anecdotes of immoral dealings however, they are not at the core of the water distribution problems.

Out of sight, out of mind?

Somewhat ironically, the root cause of the persistent problem is the ‘lock-in’ effect – that consumers have invested in the methods they have adopted to deal with an intermittent supply and are reluctant to give them up. This includes not only the system of storage tanks, but also of purification devices, booster pumps to extract more water from the mains already under low pressure, and private wells. This allows most Mumbaikars to cope with non-continuous supply of water, so the problem is effectively hidden from sight. Meanwhile, the development of high-rise buildings continues, exacerbating the problem where distribution cannot meet local demand and strengthening the lock-in of the various coping strategies.

A move towards continuous water supply requires trust to be re-established that mains will be pressurised around the clock. This will decrease demand by the amount that is now stored daily ‘for a rainy day’. Leaks also need to be fixed throughout the system, since water would be flowing and lost over 24 hours each day instead of just four. On the other hand, projects such as Mumbai’s water distribution improvement programme with Suez Environment – which is upgrading the affluent Bandra ward to a 24/7 water supply – are at the forefront of the change and demonstrate that a good quality continuous water supply is possible and desirable.

Having continuous water supply will significantly increase the quality of life of millions of Mumbaikars, and momentum is building to bring back the water supply people enjoyed six decades ago, when the ‘Island City’ had effective water pressure day and night. With this missing piece filled in, Mumbai will be significantly closer to becoming the world class city it aspires to be – a shining Shanghai on the Arabian Sea – and India as a nation will be closer to achieving the Sustainable Development Goals.

Simon’s research visit to the Council on Energy, Environment and Water (CEEW) in India was funded by the British Council through its Newton-Bhabha PhD Placements Programme

Imperial Fringe: Water Water Everywhere

Find out more about research at Imperial on everything from flood proof cities, cleaner drinking water to outer solar system oceans at Imperial Fringe, 17:00 – 20:00 on Thursday 29 September 2016.


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