Has mushrooming of borewells caused Chennai’s groundwater levels to plummet?

The groundwater tables across several localities have seen a sharp decline in just a year, shows data from Chennai’s Metrowater.

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In May 2019, R Balachander was shocked to realise that he had no water in his borewell. A first in the 40 years since the borewell was drilled and one that the long-time resident of Adyar had never anticipated.

“The borewell in my house is 94 feet deep and after it went dry, I extended it to 100 feet. I didn’t get water from it beyond two days. I spent around Rs 35,000 for that. After that, I stopped thinking about deepening the borewell and resorted to purchasing water from tankers,” he tells TNM.

Balachander’s story is one residents across several neighbourhoods in Chennai are all too familiar with.

Chennai's water crisis, considered one of the worst in 70 years, has left citizens anxious. The water-starved city has borewells in most residential dwellings. The advent of apartment complexes across the city has brought with it deeper borewells to cater to the need of a large number of housing units. These borewells have always been a reliable backup to people whenever the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) faltered in providing water.

However, the summer of 2019 has hit residents hard with Chennai’s four main reservoirs bone dry, while its groundwater levels is fast depleting. Data provided by CMWSSB shows how in a span of 12 months groundwater levels in certain localities in Chennai have gone down.

For example, in June 2018, the groundwater level in Royapuram stood at 6.97 metres (around 23 feet). The groundwater level at the same area in June 2019 is 8.09 metres (around 26.5 feet). Similarly, the water table in Thiru Vi Ka Nagar was 5.80 metres (around 19 feet) in June 2018, while a year later it stood at 8.64 metres (around 28.3 feet).



Source: Twitter/CHN_Metro_Water

“On an average, the groundwater table has gone down by 100% from earlier levels. It means in locations where people got water at 150 feet, now they have to bore for 300 feet to even get a glimpse of water,” says J Saravanan, a Chennai-based hydrogeologist.

Murugan*, a borewell operator in the city concurs with Saravanan. “In Choolaimedu and Butt Road (Ramapuram), the water levels this year is at 800 feet and 900 feet respectively. Even then finding water is very tough. Same areas, last year we were able to get water after boring 400-500 feet,” he says. He, however, adds that the situation is not too bleak in many other places. For example, while the water level below the ground in Sholinganallur in south Chennai is at 100-300 feet deep, the same in Tiruvottriyur in the north Chennai is at 20 feet. Navalur, around 10 kilometres further south from Sholinganallur, has water level at 40-45 feet, Murugan says.

But what has caused such a drastic drop in Chennai’s water tables?

Haphazard development reason for groundwater depletion

Chennai does not have any restriction as far as drilling borewells is concerned, as long as the water extracted is for domestic consumption. However, the commercial exploitation of borewells is strictly monitored by the government, at least on paper.

The current crisis has driven many residents to take steps to deepen borewells. The demand for digging borewells has never been so high as it is right now, says Murugan. “There is so much demand that we are facing labour crunch. Because of lack of workers, we are not able to take up many assignments,” he adds.

The deepening of borewells has, however, become a matter of concern for many in the city. The fear is that water levels in their borewells could drop if a neighbor has deepened his/her borewell. This is common in residential areas where individual houses and apartment complexes co-exist.

Saravanan identifies this as an effect of environmentally unsound city development. “Development must happen based on the carrying capacity of an aquifer,” he says.

Placing the blame squarely on the urban planning department, Saravanan questions the government's logic behind encouraging such development plans when it is clear that it is not sustainable.

Will rains and regulations help?

While Chennai received some amount of rain in the last few weeks, has it made any difference to the parched city?

“It is doubtful if there will be a change in the overall water table but whoever has done water harvesting in proper manner, there will be improvement for them in terms of water level and quality of water,” Saravanan explains. He also adds that in relation to groundwater, though there are no laws to address the drilling of borewells in the city, the Central Ground Water Board has a proposal to impose nationwide restrictions on the depth of borewells and explains why he thinks this proposal is unfair as of now.

“If the government is not able to supply to those pockets, then the residents are left to fend for themselves. When you (the government) are providing water, then it makes sense to place restrictions. When the government fails, they have no locus standi to even question the residents,” he says.

*Name changed upon request