The Hindu 27.03.2013
Water table in Chennai dips
Scarcity looms due to lack of rainfall, indiscriminate extraction.
Insufficient rainfall and a prolonged spell of dry weather have taken a toll on the groundwater resources in and around the city.
The water table is now at an average of four metres below the ground. This is a metre less than the level recorded at this time last year, according to data of State Ground and Surface Water Resources Data Centre, a wing of Water Resources Department.
Residents of several areas, particularly the suburbs, who are dependent on groundwater, are already feeling the heat as the water level in their open wells has come down by a few feet.
Prema Sriraman, a resident of Villivakkam, said the kind of decline in water levels seen now usually occurred in peak summer.
The water is also turning saline in many areas. The declining water level has only increased the burden on residents who are already staring at a water crisis as water levels in major reservoirs supplying drinking water to the city has come down.
Hydrogeologists in the WRD said that the localities in the southern parts of the city are worst affected as groundwater resources are over-exploited.
Besides burgeoning population, indiscriminate extraction of groundwater by private water suppliers has also led to the fall in the water table.
The water level has declined to six metres below ground in areas such as Kovilambakkam, Medavakkam, Pallikaranai and Tambaram. However, water quality has not deteriorated much compared to last year.
The total dissolved solids in water ranges between 500 parts per million to 1,200 ppm across the city according to the soil condition.
The Adyar creek is one area where the TDS level is as high as 3,000 ppm due to tidal action.
The permissible limit for drinking water is 500 ppm.
In areas such as Virugambakkam and Koyambedu, the iron content in the water will be high, they said.
Seawater incursion, though, is still at manageable levels, said officials.
Seawater has however intruded up to few hundred metres in areas close to the coast such as Besant Nagar and Thiruvalluvar Nagar, Thiruvanmiyur.
Over-exploitation by private water suppliers has affected the southern parts of the city.
