How a water crisis affected Chennai of India: one of the wettest cities in the world

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

India’s sixth largest city receives an average annual rainfall of about 1,400 mm (55 inches), more than double the amount that falls on London and nearly four times that of Los Angeles. However, in 2019 it reached the headlines for being one of the first major cities in the world to run out of water: transporting 10 million liters a day to hydrate its population. This year, it had the rainiest January in decades.

The ancient port of southern India has become a case study on what can go wrong when industrialization, urbanization and extreme climate converge and a booming metropolis stretches across the floodplain to meet the demand for new homes, factories and offices.

Formerly called Madras, Chennai is located on a low plain off the southeast coast of India, intersected by three major rivers, all heavily polluted, flowing into the Bay of Bengal. For centuries it has been a trade link connecting the Near and Far East and a gateway to South India. Its success spawned a conurbation that grew with poor planning and now hosts more people than Paris, many of them engaged in the thriving automotive, healthcare, IT and film industries.

But its geography is also its weakness.

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

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

With fewer places to contain rainfall, flooding increased. In 2015, Chennai suffered the worst flooding in a century. The northeast monsoon threw 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 were flooded outside their homes. In the computer hallway, water reached the second floor of some buildings.

Four years later it was the water shortage that hit the headlines. The city hit what it called Zero Day, as all its main reservoirs were depleted, forcing the government to walk away with drinking water. People lined up for hours to fill containers, water tanks were hijacked and violence erupted in some neighborhoods.

“Floods and water scarcity have the same roots: urbanization and construction in an area, regardless of the natural boundaries of the site,” said Nityanand Jayaraman, a writer and environmental activist living in Chennai. “The two most powerful agents of change – politics and business – have too short-sighted visions. Unless that changes, we are doomed. “

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

The northeast monsoon officially ends in December, but this winter heavy rain continued until well into January, with Tamil Nadu receiving more than ten times the normal rain of the month.

“Such heavy rainfall was not normal when my parents and grandparents were young,” said Arun Krishnamurthy, founder of the Chennai-based Non-Profit Environmental Foundation of India. “People talk a lot about weird weather here, but it doesn’t relate to climate change.”

Chennai is an extreme example of a problem that is increasingly upsetting cities around the world that are also facing a rapidly increasing population. Sao Paulo, Beijing, Cairo and Jakarta are among the urban centers suffering from severe water shortages. “It’s a global problem, not just Chennai,” Krishnamurthy said. “We need to work together to ensure a secure future for water.”

The Tamil Nadu government says it is solving the problem. In 2003, a law was passed requiring all buildings to collect rainwater. The standard helped raise the water table, but gains were soon eroded by lack of maintenance, according to the Central Groundwater Board of the Ministry of Agriculture. Efforts to recharge groundwater have also had problems compensating for the volume of water that is extracted through the holes.

The Chennai Metropolitan Sanitation and Water Board did not answer questions on the issue. The Tamil Nadu Water Supply and Drainage Board did not respond to any emails requesting comments.

Shortly after Zero Day 2019, Tamil Nadu’s chief minister, Edappadi Palaniswami, announced a public program that would include a “massive participation of women” that would cover from rainwater harvesting, saving of water and the recycling and protection of water resources, along with studies on how to clean up 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 freshwater. The plants have been criticized for causing environmental damage and negatively affecting local fisheries.

Now, the government is pursuing 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 ancient artificial lakes built around temples.

With the support of the Dutch government and the Asian infrastructure investment bank, 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 drought. months.

“Floods, drought and sanitation are related,” said Sudheendra NK, director of Madras Terrace Architectural Works, which is involved in the project. “When a critical mass of people take on 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 curb flooding and water scarcity.

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

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