CHENNAI: The increase in area with fly ash deposits and reduction in wetlands area in Ennore shows significant pollution caused by the North Chennai Thermal Power Station between 1996 and 2022 that has altered the ecosystem of the entire region, said an independent study that is part of the report submitted by the Santha Sheela Nair-led panel to the National Green Tribunal.
“It is evident, there has been a significant reduction in the total area of mangroves and waterbodies whereas the fly ash contamination area has increased multifold. This clearly shows that the mangroves and water bodies have been significantly polluted by the illegal fly ash deposition by the North Chennai Thermal Power Station. "
"Also, new developments (built-up land) and fly ash depositions in the study location have significantly reduced the natural drainage, thereby altering the hydrology and ecosystem of the entire region,” said the study by Balaji Narasimhan, noted hydrologist and professor at the Department of Civil Engineering at IIT Madras.
Narasimhan’s study titled “Report on the effects of Fly ash on the Hydrology and Hydrodynamics of Kosasthaliyar river near North Chennai Thermal Power Station (NCTPS), Ennore”, forms the core of overall report.
Fly ash in backwaters
Narasimhan estimated the total volume of fly ash deposition in the study area to be 39,83,002 cubic meters (approximately 5.67 million metric tonnes (MT)) of which 19,11,830 cubic meters (approximately 2.67 million MT) are present in the backwaters and the remaining in the flood plains. “The tidal fluctuation is considerably impacted due to the fly ash deposits,” he wrote and highlighted the disparity between the ash that should be in the dyke and the actual quantity of ash present in the dyke.
D Narasimhan, eminent botanist and member of the NGT committee, noted that salt pans, which were originally halophytic wetlands, need to be restored, not for salt, but to bring the backwater into the affected area to rejuvenate the ecosystem and to help restore the habitats for native plants to establish.
“Restoration of salt pans is an important step to revive the original character as salt marshes. This is important to restore both the salt marshes and mangroves,” he said in the report. When contacted, a senior official of the Tamil Nadu Generation and Distribution Corporation (TANGEDCO) accepted that there were occasional leaks from its fly ash pipelines. “We are fixing the leaks on short notice and are also in the process of replacing the aging pipelines. The remediation works were carried out as per NGT directions and will comply with any further orders.”
TNIE shared a copy of the NGT committee report with Deepak Srivastava, member secretary of Tamil Nadu Wetland Authority. He said a report on the status of the wetlands in Tiruvallur will be sought from the district collector.
“In January, I wrote to all the district collectors of Tamil Nadu to include wetlands in their respective District Environmental Plans. It is of extreme importance to save what is remaining. Efforts will be made to notify the wetlands in Ennore under the Tamil Nadu Wetland (Conservation and Management) Rules, 2017,” he said.
