CHENNAI: With the city recording a 55 per cent deficit in rainfall last monsoon season, reservoirs are running dangerously low and groundwater resources are under immense strain. Studies indicate that ground water levels across the city have reduced further by an average of 1-1.5 metres below the ground level since July.

According to data available with the NGO Rain Centre, average water levels in the city plunged to nearly 7.6 metres below the ground level in December compared to an average of  5.7 metres in Dec 2017.

The Rain Centre, which has been monitoring groundwater levels across the city since 2015, has found that 70 per cent of the 88 wells that they have been monitoring have gone dry this year. “In the same period last year, only 25 per cent of the wells went dry. In areas such as Koyambedu, Valasaravakkam, Virugambakkam and Mambalam we found water at three metres below the ground last year. But this year the water have drastically gone down till seven meters,” said Sekhar Raghavan, Rain Centre’s Director.
Also, it was observed that from October to  December, there has been a steady decline in water levels. In places such as T Nagar, Triplicane, Choolaimedu and Maduravoyal there has been a whopping one-metre dip. In other places such as Adyar, Vadapalani and Ashok Nagar, it has gone from seven metres to bone-dry levels this year.

Since the northeast monsoon failed and since water levels in the reservoirs are already low, experts fear that exploitation of groundwater would be very high this year.

As a result, salinity levels or the amount of Total Dissolved Solids (TDS) rate in the water table are prone to increase, especially in localities along the coastline, says Elango L, a professor with the Geology Department in Anna University.

“According to the study we carried out in August, water levels in Thiruvanmiyur have dipped to 6.22 metres. Areas such as Palavakkam, Kottivakkam and beyond are most prone to saline intrusions. The only way to bring these levels up is by rain water harvesting or installation of recharge wells,” he said.
As of Sunday, the combined capacity of four reservoirs stood at 1429 mcft, opposed to 5002 mcft last year. But officials from Metro Water say this would last for the next two months along with sufficient supply from Veeranam Tank and two desalination plants.