Chennai: Though the ground water table in the central parts of the city remains at a good level since drinking water is supplied through pipes, the ground water level at the suburban areas like Pallavaram, Chromepet, Medavakkam, Velachery and Perungalathur have fallen to dangerous levels as people depend on groundwater for all purposes including drinking.

The average ground water level in Chennai is 9.6 feet and it varies from area to area. The ground water situation in the core areas of Chennai is healthy and water is found is found within 2 to 3 feet found in places like Jaffer Khanpet, Vepery and Raja Annamalai Puram as per the statistics given by the Chennai Metro Water Supply and Sewerage Board (CMWSSB).

In areas like Iyyappanthangal, Mylapore, Besant Nagar, Kolathur and Villivakkam, the ground water remains at 5 to 8 feet. The water level has dropped below ten feet in Adyar, Nungambakkam and Anna Nagar. But the suburban areas like Pallavaram, Chrompet, Tambaram, Velachery and Medavakkam report a fall of groundwater from 300 to 700 feet.

While drinking water is supplied through pipes in the core areas of Chennai and people depend less on borewells, people in the suburban areas rely on deep borewells. The water from the borewells is pumped out using motors and most of the houses have water purifiers for drinking water. The water pumped out through borewells is purified and used by the suburban residents who depend on borewells for cooking, washing clothes, vessels, bathing and toilet purposes.

A large amount of water is used to flush and clean the toilets while washing machines take several litres of water for one washing. Though some of the companies have introduced environmentally friendly washing machines, the older ones use a large quantity of water. Multi-storey apartments with several houses in a small area of land pump out a large quantity of water through borewells, resulting in depletion of ground water.

The coastal areas in North Chennai where the depletion of groundwater is high face the risk of sea water seepage making the groundwater saline and the situation could become irreparable if sea water seepage is allowed.

In Chengalpet district, the average ground water level is 10.5 feet in the rural areas, but the water level has fallen in the areas located near Chennai such as Tambaram and Vandalur. The ground water level has dropped in the industrialised areas due to over exploitation of water.

The ground in the areas of Tambaram, Chrompet, Pallavaram and Medavakkam is rocky and this is one of the reasons for sinking the borewells for depths beyond 300 to 700 feet. Relatively, the ground in Mylapore, Triplicane, Adyar, Jaffer Khanpet and Vepery are sandy.

In Kanchipuram district too, the average level of ground water is 9 to 11 feet since a large area comes under irrigation. Most of the areas are classified as safe zones by the NAQUM (National Aquifer Mapping) programme. Here too the water table in the industrialised areas like Oragadam and Sriperumbudur has dropped from 250 to 300 feet due to over exploitation.

Though water conservation and supplying water from the water bodies and rivers could manage the situation for some time, the onset of north-east monsoon and copious rains is required to recharge the groundwater levels in the suburban areas. If the rains are delayed or if the quantity of rains goes down, the suburban areas of Chennai will face water scarcity during next year’s summer.

Even if it rains heavily, water bodies could not store sufficient water if they are not properly desilted and the encroachments are removed. The encroachments on water bodies, the catchment areas and the canals carrying water to them should be removed for effective storage of water. Storing water in the lakes and ponds will also increase the ground water level in the nearby areas.

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