With rains failing to replenish the groundwater resources for the past two years, the city’s water level is fast depleting and adding to the burden of the surface water resources in quenching the thirst of an ever-growing population.
The average water table position in Chennai was at 4.94 metres below ground level in April this year. It has depleted by more than one metre since April 2009. Though there was a slight rise in April 2012, it could not be sustained owing to deficit rains and continuous extraction.
However, the city is a better position compared to other districts like Coimbatore, Tirupur and Krishnagiri, where the water table has plummeted to a depth of 10 to 16 metre below ground level. This was revealed in a survey by the State Ground and Surface Water Resources Data Centre, Water Resources Department (WRD), which assessed the fluctuations in the water level in the State during the month of April over the last six years.
Officials of the centre said the city has been receiving deficit or near normal rainfall for the past few years. This has taken a toll on the groundwater resources of Chennai, which largely depends on rains to meet its requirements.
Krishna water from Andhra Pradesh and supply from Veeranam tank in Cuddalore district have helped maintain the drinking water supply.
Interestingly, the water table levels in Kancheepuram and Tiruvallur have marginally increased over the past six years. Declining water-intensive agriculture activity and rapid urbanisation in these districts has led to the minimal rise, despite over-exploitation of resources in some areas for city supply, officials said.
Among the 32 districts, Dharmapuri is worst hit with the water table at a depth of 10.04 m this April, signalling a severe water-stress situation. If there are no rains, the level would soon hit the lowest point of water availability in the locality, an official added.
K.R. Govindaraju, former chief engineer (groundwater), WRD, said interior districts may have interim relief from plummeting water tables, due to the current heavy rains.
Besides constructing more check dams across river and rejuvenating water bodies with inbuilt recharge wells, the government must link rivers in the State to ensure perennial flow. In Chennai, linking the Adyar and Palar rivers would help save resources that otherwise drain into the sea, he said. “Water availability in a lake or river will have an impact on the groundwater table for a minimum radius of 5 km,” he said.
