How a water crisis hit Chennai, one of the rainiest cities in the world, in India

Climate change is causing sea levels to rise and floods to rise in some cities around the world and droughts and water shortages in others. For Chennai’s 11 million people, it is both.

India’s sixth largest city receives an average of about 1,400 mm (55 inches) of rain per year, more than double the amount that falls in London and almost four times the level of Los Angeles. Still, in 2019, it made headlines for being one of the first big cities in the world to run out of water – carrying 10 million liters a day to hydrate its population. This year, it had the rainiest January in decades.

The former southern Indian port has become a case study of what can go wrong when industrialization, urbanization and extreme weather converge and an expanding metropolis is paving its floodplain to satisfy the demand for new homes , factories and offices.

Formerly called Madras, Chennai is on a low plain on the southeastern coast of India, cut by three main rivers, all heavily polluted, that flow into the Bay of Bengal. For centuries, it has been a commercial link connecting the Near East and the Far East and a gateway to southern India. Its success spawned a conurbation that grew with little planning and now houses more people than Paris, many of them involved in the thriving automotive, healthcare, IT and film industries.

But its geography is also its weakness.

The waters of the Bay of Bengal, subject to cyclones, periodically appear in the city, forcing rivers full of sewage to overflow into the streets. Precipitation is irregular, with up to 90% falling during the northeast monsoon season in November and December. When the rains subside, the city depends on huge desalination plants and piped water hundreds of kilometers away, because most of its rivers and lakes are very polluted.

While climate change and extreme weather conditions have played a role, the main culprit for the water problems in Chennai is inadequate planning. As the city grew, vast areas of the surrounding floodplain, along with its lakes and ponds, disappeared. Between 1893 and 2017, the area of ​​Chennai’s water bodies shrank from 12.6 square kilometers to about 3.2 square kilometers, according to researchers at Anna University in Chennai. Most of that loss has occurred in recent decades, including the construction of the city’s famous IT corridor in 2008 on about 230 square kilometers of swamp. The Anna University team projects that by 2030 about 60% of the city’s groundwater will be seriously degraded.

With fewer places to contain precipitation, floods have increased. In 2015, Chennai suffered its worst flood in a century. The northeast monsoons poured up to 494 mm (19.4 inches) of rain into the city in a single day. More than 400 people died in the state and 1.8 million people were left without their homes. In the IT corridor, water reached the second floor of some buildings.

Four years later, it was the lack of water that made headlines. The city hit what it called Day Zero when all of its main reservoirs dried up, forcing the government to transport drinking water by truck. People stood in lines for hours to fill containers, water tanks were hijacked and violence broke out in some neighborhoods.

“Floods and water scarcity have the same roots: urbanization and construction in one area, regardless of the natural limits of the place,” said Nityanand Jayaraman, a writer and environmental activist who lives in Chennai. “The two most powerful agents of change – politics and business – have very short-sighted views. Unless that changes, we are doomed. “

Tamil Nadu, the state of which Chennai is the capital, predicts in its action plan for climate change that the average annual temperature will rise by 3.1 ° C by 2100 from 1970-2000 levels, while annual rainfall will fall by up to 9% . Worse still, rainfall during the southwest monsoon from June to September, which normally brings the constant rain needed for cultivation and replenishment of reservoirs, will decrease, while the cyclone season, which tends to flood in winter, will become more intense. This can mean worse floods and droughts.

The northeast monsoons officially end in December, but this winter the heavy rain continued until January, with Tamil Nadu receiving more than 10 times the normal rainfall for the month.

“These heavy rains were not normal when my parents and grandparents were young,” said Arun Krishnamurthy, founder of the Chennai-based nonprofit India Environmental Foundation. “People here talk a lot about the strange weather, but they don’t associate it with climate change.”

Chennai is an extreme example of a problem that is plaguing more and more cities around the world that are also struggling with rapid population growth. São Paulo, Beijing, Cairo and Jakarta are among urban centers that face severe water shortages. “It is a global problem, not just Chennai,” said Krishnamurthy. “We need to work together to ensure a water security future.”

The Tamil Nadu government says it is addressing the problem. In 2003, it passed a law requiring all buildings to collect rainwater. The rule helped to raise the water table, but the gains were soon eroded by the lack of maintenance, according to the Central Council for Groundwater of the Ministry of Agriculture. Efforts to recharge groundwater have also faced difficulties in compensating for the volume of water extracted through boreholes.

The Chennai Metropolitan Water Supply and Sewerage Council did not respond to questions on the matter. The Tamil Nadu Water Supply and Drainage Council did not respond to an email requesting comments.

Shortly after Day Zero 2019, Tamil Nadu Chief Minister Edappadi Palaniswami announced a public program that would include a “massive participation of women” covering everything from rainwater collection, water saving and recycling and protection water resources, along with studies on how to clean the state’s polluted rivers.

Until then, the government’s strategy had focused on building large desalination plants, an expensive tactic, most commonly associated with arid nations or islands with limited fresh water. The plants have been criticized for causing environmental damage and having a negative impact on local fisheries.

Now, the government is looking for a new approach inspired by the city’s past. The Greater Chennai Corporation is supporting an initiative called City of 1,000 Tanks, a reference to the ancient man-made lakes that were built around temples.

With the support of the Dutch government and the Asian Infrastructure Investment Bank, the plan is to restore some temple tanks and build hundreds of new ones with green slopes across the city to absorb and filter heavy rain, recharge the water table and store water for use during dry months.

“Floods, droughts and sanitation are all linked,” said Sudheendra NK, director of Madras Terrace Architectural Works, which is involved in the project. “When a critical mass of people take over all of this, a significant difference will be noticed and we will no longer be in crisis.” He said it would take at least 5 years for the project to have an impact.

Meanwhile, Chennai continues to add a quarter of a million people a year, making it a race against time to contain floods and water scarcity.

“My fear is that these things will happen more often in the future,” said Krishnamurthy. “We didn’t learn the ‘Zero Day’ lesson.” – By Anurag Kotoky and Karoline Kan

– With the help of Ganesh Nagarajan, Jody Megson and Jin Wu