Why Chennai, India’s Sixth Biggest City, Has Run Out of Water

Satellite imagery showing Chennai’s Lake Puzhal, Chennai’s largest reservoir, in February 2019 and again June 2019.
GIF: ESA Sentinel Hub

In what’s becoming an increasingly common story, a major city has run out of water. Chennai, India is home to 4.65 million and a severe deficit of water to serve their needs.

Reservoirs have turned into muddy splats on the landscape and the city is relying on mix of desalination plants and water being brought in by train and truck to quell unrest. The drought is indicative of morass of issues increasingly stressing water supplies not just in Chennai but around the world: poor management, overusing groundwater, and a shifting climate turning the hydrological cycle on its head. And if the world’s water insecure cities don’t act, they could be the next Chennai.

This week in Chennai began with a city official telling the BBC that “[o]nly rain can save Chennai from this situation.” And while a few showers fell on Thursday, they’re not nearly enough to reverse the catastrophic situation in the region. Residents have been turning to water trucks to fulfill their daily needs, but that also comes at a hefty cost. Raj Bhagat, World Resources Institute’s sustainable cities manager in India, told Earther that scarcity means the truck operators “sell water at very high prices… making it difficult for weaker sections of the population.”

The city had gone nearly 200 days without rain, and after a weak 2018 North East monsoon season that runs from October-December, the four reservoirs that serve the city began to wither away earlier this year. Add in the intense heat that gripped India in May (though the worst of it was to the north of Chennai) and the withering process went into overdrive as water evaporated into the cloudless sky.

Climate change has an influence on heat waves, raising the risks of more evaporation and baking in drought by sucking moisture out of the soil. Background warming has also raised Chennai’s temperatures about 1.3 degrees Celsius (2.4 degrees Fahrenheit) over the past 60 years meaning even without heat waves, climate change is altering the hydrological cycle. But the problems for Chennai’s water supply extend beyond low rainfall.

Seven months in the life of a disappearing reservoir.
GIF: ESA Sentinel Hub

“The issue plaguing Chennai is a mix of over consumption and low rainfall during 2018 North East Monsoon,” Bhagat said. “The city and its neighbouring region has witnessed massive growth in all sectors over the last century which had resulted in massive [increases in water] consumption.”

Indeed, the city has seen its population grow by double digit percentages every decade since the 1940s. The huge growth coupled with weak planning has led to a water system that’s both overtaxed and widely inefficient. The rapid urbanization has also paved over once permeable surfaces, reducing groundwater recharge rates. Chennai’s reservoir capacity also remains well below what’s needed to serve the population and there’s no water metering program in place, meaning already scarce water resources aren’t being monitored for overuse.

In short, it’s the perfect storm of human failures and a harsher climate coming together create huge issues for the city’s residents. City managers have been looking into installing more desalination capacity to cope with future droughts, but Bhagat suggested other investments in better water infrastructure might pay more dividends and be less costly. Among them are harvesting more rainwater, starting a water reuse program, improving irrigation efficiency upstream so more water makes it to reservoirs and conserving flood plains and lakes.

Chembarambakkam Lake from December 2018 to June 2019.
GIF: ESA Sentinel Hub

These types of choices are ones cities are increasingly facing around the world as more people move into them and rainfall becomes increasingly erratic in many places. In Cape Town, reservoirs turned to dust last year in a preview of what the future climate holds. The city averted a full blown crisis through a massive water conservation program and considered tapping underground aquifers to avert future dalliances with Day Zero, though doing so would likely cause significant environmental harm. Sao Paulo ran out of water in 2015, again due to a debilitating drought and poor management. Los Angeles, San Francisco, and the rest of California left a multiyear drought behind thanks to record rains in 2018 and 2019, a pattern of weather whiplash likely to become more prominent as the world warms.

The water wars are knocking on our doorsteps, and cities all have choices to make for how to keep them at bay.


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