The groundwater table across the State has been receding steadily over the past five years sending strong signals about the impact of indiscriminate water drawal following unrestrained urbanisation and lack of recharge.
Deficit rainfall last year in many districts in general and the failure of the northeast monsoon in particular have only made the situation worse in most districts.
Places such as Coimbatore, Salem, Erode and Tiruppur have seen a steady decline in the groundwater table over the past five years, data shows.
According the State Ground and Surface Water Resources Data Centre of the Water Resources Department, the water table in Coimbatore has plunged below 16 metres in the past one year. Similarly, the water table in districts such as Salem, Namakkal, Theni and Erode is alarmingly low now.
The Nilgiris district is perhaps the only district that has witnessed a marginal rise in the water table. Chennai’s water table too has seen marginal increase in the past five years. But, this is only due to the groundwater recharge after the torrential downpour in 2015, and it has started declining again.
Officials of the State Ground and Surface Water Resources Data Centre said that the groundwater table in the Nilgiris district often does not reflect the rainfall pattern because of the geological formation there. Despite poor rainfall in the Nilgiris district, the observation wells indicate a marginal increase in the water level. This is because the source of water for that particular place in the Nilgiris is located in another region.
Though districts like Dharmapuri and Ramanathapuram are traditionally known to be water-starved, they are better placed compared to some other districts in the western region.
The water table in districts like Salem, Namakkal and Coimbatore is dismal because of fewer sand aquifers that allow water percolation, erratic rainfall pattern and over-exploitation of water resources without much recharge, officials said.
The data is compiled based on the reading of over 5,100 observation wells across the State.
