CHENNAI: The water crisis in Chennai has forced residents to dig deeper borewells — even to 1000 ft at some places — at astronomical costs to meet their needs. This, even as groundwater depletion in the city has become so severe that Rain Centre, an organisation working to protect water resources, said 60 per cent of the observation wells maintained by it have dried up in the past month.
Rain Centre said 52 out of their 88 observation wells had no water even at 30 feet, with Chetpet, Koyambedu, Vadapalani and Mylapore among the most parched. Wells in other areas have seen a drop of an average of 0.5 metres since May. In Maduravoyal, groundwater levels have plummeted from 9.25 metres to 10.4 metres in just a month. The organisation said the groundwater column had receded from 15ft to 30ft in the city in the past three years, with the current situation much worse than during 2017. In June 2017, groundwater levels had dropped to an average of 5.4m, while this month the levels have dropped to nearly 8.8m.
Experts said levels had dropped to 300-400 ft in Central Chennai, 700 ft in South Chennai and 800-900 ft in North Chennai, leading to a 150 per cent increase in borewell installation charges in the past two months. “We need 750-800mm of continuous rainfall to replenish the aquifer,” said a TN groundwater resources centre official.
“December 5, 2018, was the last day the city received rains. But we weren’t able to divert this to the groundwater table due to structures like stormwater drains diverting rainwater into the sea. In the coming days, more and more observation wells are likely to go dry,” warned Rain Centre director Sekhar Raghavan. It may be recalled that a Niti Aayog report had said that Chennai would completely run out of groundwater by 2020.
However, residents had little choice, said experts. “Metro Water tankers come only once in three weeks, private tankers fleece residents and tapped water from Metro Water comes only twice a week in most parts,” said J Saravanan, a hydrologist.
This has resulted in a 150 per cent increase in borewell installation charges over the past two months, according to experts. “Contractors used to charge Rs 350- Rs 400 per foot for drilling through the shallow aquifer and Rs 75- Rs 80 for hard rock layer. Now they are charging Rs 400 per ft for both layers combined,” said Saravannan.
Borewell contractors said that as water was not available in the shallow aquifer, they had to dig deeper in search of water till the hard rock layer.
Once Tamil Nadu passed its groundwater extraction regulations, illegal exploitation could be controlled to an extent, said the official from the groundwater resource centre.
Relief in sight?
The heat wave troubling Chennai and neighbouring districts is likely to subside from this weekend. Met officials say conditions are becoming favourable for the advance of the monsoon.