WRD to take up large scale recharge shafts project in January to boost groundwater table in T.N.

After a gap of nearly five years, the Water Resources Department (WRD) will start work in January to install artificial recharge shafts across 23 districts to replenish groundwater level in over-exploited and critical blocks in the State.

While artificial recharge shafts have been installed in the past, the WRD’s State Ground and Surface Water Resources Data Centre will implement the project on a large scale for the first time in several years to boost the groundwater table.

The project involves drilling 576 artificial recharge shafts across districts, including Tirupattur, Vellore, Karur, Ranipet, Thanjavur, Salem, Cuddalore, and Villupuram. Recharge shafts would also be installed in Tirunelveli, Ramanathapuram, and Sivaganga to improve declining water quality. Places like Chennai would be covered in the next phase.

Tender is being finalised for the ₹6.74 crore project, and administrative process has delayed the work. Officials of the WRD said the vertical structures would channel rainwater runoff into deep aquifers and recharge groundwater in areas experiencing severe depletion.

Sites have been chosen based on lithology, declining water levels and quality, as indicated in survey reports prepared by a team of geologists. These structures would be constructed near water bodies and storage structures like check dams to ensure faster infiltration.

According to the Central Ground Water Board’s ‘National Compilation on Dynamic Groundwater Resources of India 2025,’ nearly 32.91% of the 313 assessment units in taluk level have been identified as over-exploited, while 7.35% units fall under the critical category where more than 90% of available groundwater has been extracted. Tirupattur, Vellore, Salem, and Perambalur are among the districts where over 75% of blocks have been identified as over-exploited.

However, the State’s total annual groundwater recharge has marginally increased from 21.51 billion cubic metre (bcm) in 2024 to 22.61 bcm this year. According to CGWB, the stage of groundwater extraction of the State has declined marginally from 74.26% last year to 73.50% this year.

Officials of the WRD said the structures would be drilled to a depth ranging from 10 metre to 100 metre to reach deep aquifers, and enable 30% more recharge than natural process. About 100 of them would also function as monitoring wells, adding to the existing network of nearly 4,300 monitoring wells across the State.

Officials said once the recharge shafts are installed in four months, groundwater impact would be studied through monthly and annual assessments. “We expect some blocks to move to semi-critical and safe category in the next few years. The impact of the structures can be felt for a radius of 500 metre to 1 km,” said an official.