To mitigate floods and reduce seawater intrusion, the Tamil Nadu Water Resources Conservation and River Restoration Corporation plans to revive waterbodies near the coastline in 15 districts. As a pilot initiative, it plans to study rejuvenating waterbodies between Besant Nagar in Chennai and Kovalam in Chengalpattu district for better groundwater recharge.
The corporation, which is functioning under the Water Resources Department (WRD), was formed to promote water conservation, climate resilient infrastructure, and modernise irrigation infrastructure. With an aim to formulate a programme to prevent seawater intrusion and enhance groundwater recharge, the corporation has proposed to restore waterbodies within 15 km inland from the coastline in 15 districts. Sources said the waterbodies would be rejuvenated to store excess floodwater and boost groundwater recharge. The feasibility of diverting floodwater run-off through supply channels to tanks would also be studied.
To start with, the corporation has submitted a proposal to carry out a ₹6.51-crore pilot project to the Union Ministry of Water Resources to study and rejuvenate waterbodies between Besant Nagar and Kovalam. The proposal has been sent through the Central Groundwater Board. These waterbodies have been chosen in localities where seawater intrusion is predominant, affecting the groundwater aquifer.
Fourteen tanks, which are in flood-prone areas, have been identified in Padappai and Thiruporur blocks to be deepened and desilted for groundwater recharge and diluting salinity. Waterbodies in Semmancheri, Ottiyambakkam, Medavakkam, Sithalapakkam, Polacheri, and Amoor have been chosen for the study.
It was found that the groundwater level in the pilot study area declined to 3.90 m below the ground level during summer. According to data from the WRD’s State Ground and Surface Water Resources Data Centre, the total dissolved solids, a parameter indicative of water quality, was over the permissible limit in areas such as Neelankarai, Palavakkam, Kovalam, and parts of Besant Nagar. Citing indiscriminate groundwater extraction owing to urbanisation and water stress as reasons for the project, the corporation said building artificial recharge structures and improving the storage capacity of tanks would augment groundwater quality and arrest seawater ingression in coastal belt.
G. Sathish of Semmencheri, said: “We rely on Metrowater supply or private suppliers for our daily needs. The area’s proximity to coastline and excessive groundwater extraction has led to an increase in salinity. The government agencies must introduce stringent policies for groundwater management, enhance Metrowater supply, and regulate private water supply.”
The corporation would use satellite imagery and Geographic Information System techniques and analyse aquifer and seawater incursion through a simulation model, choose sites for groundwater observation wells, and identify the waterbodies.
After the pilot project is completed, the scheme would be expanded to other coastal districts, sources said.
Published – April 15, 2025 12:19 am IST
