Groundwater in over 30 per cent of firkas in TN over-exploited: WRD report

Groundwater in over 30 per cent of firkas in TN over-exploited: WRD report

CHENNAI: A total of 57% of the 1,202 firkas surveyed by the Water Resources Department for groundwater use have been classified as over-exploited (395, nearly 30%), semi-critical (227) or critical (64). Firkas (or revenue blocks) are a group of revenue villages.

According to WRD’s assessment report for the year 2023-24, firkas are classified as over-exploited if the stage of groundwater extraction (SoE), a measure of annual ground water extraction over annual extractable ground water resource, is 100% or more.

It means that the extraction is more than the capacity to recharge. The firkas are classified as semi-critical if the SoE is 70% to 90 % and critical when it is 90% to 100 %.

Expressing concern over 395 firkas being classified as over-exploited, farmers have requested that the state government take measures to prevent groundwater exploitation, considering the future requirements.

KV Elankeeran, president, Federation of Cauvery Delta Farmers Association, told, “Historically, the state has had numerous tanks, lakes, and linkage channels and canals. Excess rainwater would naturally flow into nearby lakes and tanks during the rainy season through designated channels. But most of the waterbodies and their surrounding areas are occupied nowadays. There is no way for water to flow logically”.

“To avoid groundwater exploitation, the state should increase rainwater harvesting and create awareness. More check dams must also be built to improve groundwater recharge.”

K Subramanian, state general secretary, Tamil Nadu Farmers Association, urged the state to identify channels that have disappeared and restore them.

A senior WRD official told, “The 1202 firkas are categorised into five types: overexploited, critical, semi-critical, safe, and saline or poor quality, based on groundwater level, rainfall, and groundwater usage.”

The WRD has installed around 900 Digital Groundwater Level Recorders to continuously monitor water levels. Steps are being taken to install these devices in all 1202 firkas, he said.

He added, “To improve the groundwater level, check dams will be constructed at 10 places in the Cauvery and Vaigai basins, while the WRD plans to build subsurface dykes in the tail-end areas of the Cauvery basin. This will also prevent sea water intrusion. Once the government issues orders, work will start.”