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

Climate change is driving rising sea levels and more flooding in some cities around the world and drought and water shortages in others. For Chennai’s 11 million residents, it’s both.

India’s sixth largest city receives an average of about 1,400 mm (55 inches) of rain per year, more than twice as much as London and nearly four times as much as Los Angeles. But in 2019 it made headlines for being one of the first major cities in the world to run out of water – 10 million liters a day transported to hydrate the population. This year it had the wettest January in decades.

The old South Indian port has become a case study of what can go wrong when industrialization, urbanization and extreme weather converge and a thriving metropolis paves its floodplain to meet the demand for new homes, factories and offices.

Chennai, formerly called Madras, is located on a lowland plain on the southeast coast of India, bisected by three major rivers, all heavily polluted, that flow into the Bay of Bengal. For centuries it has been a trade link linking the Near and Far East and a gateway to South India. Its success led to an agglomeration that grew with sparse planning and now houses more people than Paris, many of whom are engaged in thriving automotive, healthcare, IT and film industries.

But its geography is also its weakness.

The cyclone-sensitive waters of the Bay of Bengal periodically pour into the city, causing the sewage-filled rivers to flow back into the streets. Rainfall is uneven, with up to 90% falling during the northeast monsoon season in November and December. When it rains, the city has to rely on massive desalination plants and water delivered hundreds of miles away, as most of its rivers and lakes are too polluted.

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

With fewer places to hold rainfall, flooding increased. In 2015, Chennai suffered the worst flood in a century. The northeast monsoon threw a whopping 494 mm (19.4 inches) of rain on the city in one day. More than 400 people in the state were killed and 1.8 million people were flooded from their homes. In the IT corridor, water reached the second floor of some buildings.

Four years later, it was a shortage of water that made headlines. The city hit what it called Day Zero when all of its main reservoirs ran dry, forcing the government to import drinking water. People lined up for hours to fill containers, water tankers were hijacked and violence broke out in some neighborhoods.

“Floods and water scarcity share the same roots: urbanization and construction in an area without the natural boundaries of the place,” said Nityanand Jayaraman, a writer and environmentalist living in Chennai. “The two most powerful agents of change – politics and business – have visions that are too shortsighted. Unless that changes, we are doomed. “

Tamil Nadu, the state of which Chennai is the capital, predicts in its Climate Change Action Plan that the mean annual temperature will rise by 3.1 ° C from 1970-2000 levels by 2100, while annual rainfall will decrease by as much as 9%. Worse, rainfall during the June-September southwest monsoon, which typically brings the steady rains needed to grow crops and replenish reservoirs, will diminish, while the flood-prone cyclone season will intensify in winter. That could lead to worse floods and droughts.

The northeast monsoon officially ends in December, but this winter the heavy rains continued well into January, with Tamil Nadu receiving more than 10 times the normal rainfall in that month.

“Such heavy rainfall was not normal when my parents and grandparents were young,” said Arun Krishnamurthy, founder of the Chennai-based non-profit Environmentalist Foundation of India. “People here talk a lot about the weird weather, but they don’t link it to climate change.”

Chennai is an extreme example of a problem that is increasingly disrupting cities around the world that are also struggling with rapid population growth. Sao Paulo, Beijing, Cairo and Jakarta are among the urban centers with severe water scarcity. “It’s a global problem, not just Chennai,” said Krishnamurthy. “We need to work together to ensure we have a water-safe 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 raise the water table, but profits were soon eroded due to lack of maintenance, the Ministry of Agriculture’s Central Groundwater Council said. Attempts to recharge groundwater have also struggled to compensate for the volume of water extracted through boreholes.

The Chennai Metropolitan Water Supply and Sewerage Board did not respond to inquiries regarding the matter. The Tamil Nadu Water Supply and Drainage Board did not respond to an email asking for comment.

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

Until then, the government’s strategy has focused on building large desalination plants, a costly tactic more commonly associated with arid lands or islands with little fresh water. The plants have been criticized for causing environmental damage and negatively impacting local fisheries.

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

Supported by 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 throughout the city to collect and filter heavy rainfall, replenish groundwater and collect water. to store for use during dry periods. months.

“Flooding, drought 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 picks up 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 annually, making it a race against time to curb the floods and water shortages.

“I’m afraid these things will happen more often in the future,” said Krishnamurthy. “We haven’t learned the lesson from ‘Day Zero’.” – By Anurag Kotoky and Karoline Kan

– With help from Ganesh Nagarajan, Jody Megson and Jin Wu