CHENNAI: There has been a slight
rise in the groundwater table in eight zones in the city but seven others recorded a decrease, Metrowater officials said.
Tests are conducted to check the groundwater level every month. When Metrowater officials conducted the test in September, they found that the water level had increased by 0.68m, compared to the August reading, in
Madhavaram, Ambattur, Anna Nagar, Teynampet, Valasaravakkam, Adyar, Perungudi and Sholinganallur.
Officials said the rise could be a result of the 58.3mm rain the city received last month. Besides, these areas have clay soil which allows for better percolation of rain water. But the soil does not retain the water for a long period, an official said.
In Tiruvottiyur, Manali, Tondiarpet, Royapuram, Thiru Vi Ka Nagar, Kodambakkam and
Alandur, officials recorded a slight dip in the groundwater level. The decline ranged from 0.06m to 0.26m, the official said. Tiruvottiyur, Manali, Tondiarpet and
Royapuram are sandy areas, where only a slow rise in groundwater level can be recorded but the soil allows better retention of water, he added.
The official added that Metrowater had identified 145 observation wells across the city where water levels and the Total Dissolved Salts (TDS) in the water is tested every month. As per the World Health Organisation, the minimum permitted TDS is 500 parts per million (ppm) and the maximum 2,000ppm.
Of the 15 zones, eight recorded a minimum TDS of 300ppm. In Thiru Vi Ka Nagar, the minimum TDS hovered at 900ppm. On the other end, Shollinganallur recorded a maximum TDS level of 3,000ppm .