CHENNAI: In a move to effectively preserve the ecology of Ramsar sites in the State, the Tamil Nadu State Wetland Authority (TNSWA) has decided to undertake drone-based mapping and conduct Geographic Information System (GIS) analysis of such internationally important wetlands in the State.

As per a TNSWA document, the drone, Light Detection and Ranging (LiDAR), and bathymetric surveys will be done in 15 Ramsar sites, including Vedanthangal bird sanctuary, Pichavaram mangrove, Longwood Shola Reserve Forest in The Nilgiris, Nanjarayan bird sanctuary, Kazhuveli bird sanctuary, and Karaivetti bird sanctuary.

Under the initiative, land-use and land-cover classification maps will be prepared for the wetlands and their surrounding buffer areas within a minimum of 300 metres. Experts will also conduct sedimentation analysis through bathymetric surveys, both pre and post-monsoon, to identify areas that have high silt or sludge deposits.

Also, hydrological and water flow analysis will be done and studied to understand evapotranspiration rates, sedimentation rates, groundwater interaction, flood mapping, and risk assessment. Banking on advanced technologies, TNSWA will also detect and monitor invasive species within the surveyed wetlands using machine-learning and classification techniques. Biodiversity assessments, including flora and fauna surveys, vegetation health analysis, and biomass estimation are also part of the exercise.

The initiative is a part of the Tamil Nadu Wetlands Mission, under which the authority has been entrusted to undertake the ecological restoration of 100 wetlands across the State.

Presently, there are 18 Ramsar sites in Tamil Nadu, of which 17 received the international recognition after 2021. In August 2024, the Nanjarayan bird sanctuary in Tirupur and the Kazhuveli bird sanctuary in Villupuram received the Ramsar tag. Karaivetti bird sanctuary in Ariyalur district and Longwood Shola reserve forest in the Nilgiris were granted the recognition in January.

The State Environment and Climate Change Department has already initiated steps to prepare integrated management plans for most of the Ramsar sites, including Pallikaranai marshland in Chennai.