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

Climate change is leading to rising sea levels and rising floods in some cities around the world, and drought and water scarcity in others. For the 11 million people in Chennai, they are both.

India’s sixth largest city receives an average of about 1,400 mm (55 inches) of rainfall per year, more than twice the amount that falls on London and almost four times the level of Los Angeles. However, in 2019 it came to the fore in the fact that it was one of the first big cities in the world to run out of water – transporting trucks in 10 million liters a day to hydrate its population. This year, it had the wettest January in decades.

The old port of southern India has become a case study in what can go wrong when industrialization, urbanization and extreme weather converge and a booming metropolis opens over the floodplain to meet the demand for new homes, factories and offices.

Formerly called Madras, Chennai is located on a low plain on the southeast coast of India, intersected by three major rivers, all heavily polluted, which flow into the Bay of Bengal. For centuries it has been a trade link between the Near and Far East and carries it to southern India. Its success has given rise to a congestion that has grown with insufficient planning and now houses more people than Paris, many of them employed in the thriving automotive, healthcare, IT and film industries.

But its geography is also its weakness.

The waters of the Bay of Bengal, prone to cyclones, periodically flow into the city, forcing back sewer-filled rivers to flow into the streets. Rainfall is uneven, with up to 90% during the northeast monsoon season in November and December. When the rains fail, the city must rely on huge desalination plants and water conducted hundreds of miles away, because most of its rivers and lakes are too polluted.

While climate change and extreme weather have played a role, the main culprit for water problems in Chennai is poor planning. As the city grew, vast areas of the surrounding floodplain, along with its lakes and ponds, disappeared. Between 1893 and 2017, the surface of water bodies in Chennai decreased from 12.6 square kilometers to about 3.2 square kilometers, according to researchers at Anna University in Chennai. Most of this 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 team at Anna University projects that by 2030 about 60% of the city’s groundwater will be critically degraded.

With fewer places to hold rainfall, floods have increased. In 2015, Chennai suffered the worst flooding in the last century. The northeast monsoon threw up to 494 mm (19.4 inches) of rain over the city in a single day. More than 400 people in the state were killed and 1.8 million were flooded from 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 Zero Day because all its main tanks dried up, forcing the government to truck in drinking water. People have been waiting for hours to fill containers, water tanks have been hijacked and violence has broken out in some neighborhoods.

“Floods and water scarcity have the same roots: urbanization and construction in an area, mindless of the natural boundaries of the place,” said Nityanand Jayaraman, a writer and environmental activist living in Chennai. “The two strongest agents of change – politics and business – have too short-sighted visions. If that doesn’t change, we are doomed. “

Tamil Nadu, the capital of which Chennai is the capital, predicts in its climate change action plan that the average annual temperature will rise by 3.1 ° C by 2100 from 1970-2000, while annual rainfall will fall by up to 9%. Worse, rainfall during the southwest monsoon in June-September, which usually brings the constant rain needed to grow crops and fill reservoirs, will be reduced, while the winter-prone cyclone season will become winter. more intense. This could mean more severe floods and droughts.

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

“Such heavy rainfall was not normal when my parents and grandparents were young,” said Arun Krishnamurthy, founder of the nonprofit Indian Environment Foundation in Chennai. “People here talk a lot about weird weather, but they don’t relate it to climate change.”

Chennai is an extreme example of a problem that is increasingly disrupting cities around the world, which are also facing rapid population growth. Sao Paulo, Beijing, Cairo and Jakarta are among the urban centers facing a severe water shortage. “It’s a global issue, not just Chennai,” Krishnamurthy said. “We need to work together to make sure we have a secure future for water.”

The Tamil Nadu government says it is addressing the issue. In 2003, it passed a law requiring all buildings to collect rainwater. The rule has helped raise groundwater levels, but the gains were soon eroded by lack of maintenance, according to the Ministry of Agriculture’s Central Groundwater Council. Groundwater recharge efforts have also sought to compensate for the volume of water extracted through drilling.

The Chennai Metropolitan Council for Water Supply and Sewerage did not answer questions about the issue. The Tamil Nadu Water Supply Council did not respond to an email requesting comments.

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

Until then, the government’s strategy focused on building large desalination plants, an expensive tactic more commonly associated with arid nations or limited freshwater islands. The plants have been criticized for causing damage to the environment and having a negative impact on local fishing.

Now, the government is pursuing a new approach inspired by the city’s past. Greater Chennai Corporation supports an initiative called the City of 1,000 Tanks, a reference to ancient artificial lakes built around temples.

Supported by the Dutch government and the Asian Bank for Infrastructure Investment, the plan is to restore some of the temple’s tanks and build hundreds of new ones with green slopes throughout the city to absorb and filter heavy rains, recharge groundwater and store water for use during dry months.

“Floods, drought and sewerage are all interconnected,” said Sudheendra NK, director of Madras Terrace Architectural Works, which is involved in the project. “When a critical mass of people take all this, then there will be a significant difference 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 gather a quarter of a million people a year, making it a race against time to reduce flooding and water shortages.

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

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