CHENNAI: The Tamil Nadu government has commenced a Rs 50 crore restoration project with the support of the World Bank to save Kariyachalli Island, one of 21 islands in the Gulf of Mannar Marine National Park, as part of the Tamil Nadu SHORE (Sustainably Harnessing Ocean Resources) initiative.
This ambitious effort aims to combat severe coastal erosion, protect marine biodiversity, and ensure the island’s survival and stability, which is critical for ecological and community benefits, especially among small-scale fisherfolk who depend on this ecosystem.
Kariyachalli has lost over 71% of its landmass, shrinking from 20.85 hectares in 1969 to just 5.97 hectares by 2018, with experts warning that it could vanish entirely by 2036 if current erosion trends continue.
To address this crisis, the project will deploy 8,500 multipurpose artificial reef modules around the island, designed by IIT Madras based on wave dynamics and bathymetry studies. Officials told TNIE that the work has already commenced with a collection of comprehensive baseline data, and the reef construction will begin now, followed by deployment in the IIT-recommended layout around the island.
These trapezoidal structures, made of ferrocement and steel with perforations to support nutrient flow, with a height of 2 and 3 metres and weighing 1.8 and 3 tonnes respectively, are strategically placed to reduce wave energy, encourage sediment deposition, and create habitats for marine life.
The reefs are expected to stabilise the shoreline and foster ecological recovery, drawing inspiration from the successful restoration of Vaan Island, where over 10,000 reef modules increased land area and shallowed the surrounding waters, indicating sediment accumulation and supporting the growth of over 37 branching and massive coral species.
“Parallel to erosion control, degraded coral reefs and seagrass beds covering 2 acres and 3 acres, respectively, are being rehabilitated near Kariyachalli Island through standardised scientific restoration techniques. These ecosystems support species like dugongs, contribute to carbon sequestration, and protect shorelines. The project’s ecological efforts aim to further enhance these gains, ensuring that the Gulf of Mannar remains a thriving marine habitat,” said Supriya Sahu, Additional Chief Secretary, Environment, Climate Change and Forests Department.
Community involvement is a cornerstone of the project, with coastal villages like Vaipar, Sippikulam, and Pattinamaruthoor, within a 10-km radius of the island, set to benefit. The initiative seeks to provide alternative livelihoods for local communities.