Around 85% of the invasive water hyacinth covering Nanjarayan Bird Sanctuary lake in Tirupur district has been removed during a 98-day restoration operation, reopening parts of the habitat and prompting the return of birds, officials and project representatives said.
The progress was reviewed during a joint site inspection by D Venkatesh, chief conservator of forests and field director of Anamalai Tiger Reserve; Rajesh Boje, district forest officer of Tirupur division and deputy director of Anamalai Tiger Reserve; and Tirupur collector Dr Manish Narnaware. The review focused on the restoration of the district’s only bird sanctuary, which was notified in 2022.
The removal work is being led by the forest department with funding support from VETRY Trust. VETRY Trust president T R Sivaram said the organisation was prepared to support the sanctuary for the next 10 years with funding, materials and manpower. The proposed long-term support is intended to help protect the habitat after the current clearance operation is completed.
According to VETRY CEO Natraj Muthusamy, aerial mapping found water hyacinth across about 200 acres of the lake’s roughly 400-acre area. The extensive weed cover was linked to a decline in bird visits after the sanctuary was notified. The invasive plant formed dense mats over the water, reducing the open-water area available to birds and affecting conditions within the lake.
The operation uses a mechanised process. A Komatsu custom aquatic boat cuts and moves the weed mats towards the bund. An excavator fitted with a modified back bucket then drains and loads the removed biomass into tractors. Two tractors and additional vehicles are being used continuously to transport the material.
Project representatives said ducks and geese had begun returning in larger numbers as open-water patches expanded. Deep-swimming birds, including cormorants, were also reported to be returning as sunlight and oxygen levels improved in the cleared sections. These observations were cited as early signs of habitat recovery, although the operation remains incomplete.
About ₹30 lakh has been spent so far, with the total cost projected at ₹40-45 lakh. Manual teams are expected to clear the remaining pockets of water hyacinth, particularly areas that cannot be reached effectively by the mechanised equipment.
The next challenge is preventing the weed from returning. Bamboo or steel filters are planned for the lake’s inlets to limit the entry and spread of water hyacinth. The proposed measures indicate that the restoration effort is being treated not only as a one-time clearance exercise but also as an attempt to manage the conditions that allow the invasive plant to re-establish.
The forest department and its partners have not announced a separate long-term monitoring framework beyond the proposed support and inlet filters. The immediate operational milestones are the completion of the remaining manual clearance, transport of the extracted biomass and installation of measures intended to reduce re-infestation.
