Chennai: Global warming and consequent rising seawater levels are no more global phenomena. The intrusion of the eroding sea is a serious local issue pertaining to Tamil Nadu.
A team of geologists associated with Geological Survey of India (GSI) and the Union ministry of mines, who undertook an inspection trip along the eastern coast of Tamil Nadu covering Kanyakumari, Tirunvelveli, Nagapattinam, Ramanathapuram, Cuddalore, Kancheepuram districts recently, found that in more than 12 Tamil Nadu beaches the shoreline has eroded with the sea entering the mainland, ranging from 50 metres to half a kilometer in a few stretches over the past four decades.
In some pockets, the geologists of the marine division of GSI found unconsolidated sand rock stones with fossils representing both marine and riverine ecosystem. This, according to deputy director general of GSI Mr. S Raju, could be due to the depletion of river basins and estuaries with the sea taking over the main land area in TN districts.
During the trip which concluded last week, the team inspected minerals, beach sand, sand dunes, rock formations, corals, fossils, beach berm (high tide surface) and the slope of the beach. Soil samples have been collected for lab tests to detect the composition of rare earth substances.
While the southern districts have rich diversified beaches with minerals, the northern districts had lesser nutrients along their coast, deputy director general of GSI Raju said. “During our interaction with local stake holders and the satellite images taken post-tsunami revealed that the groynes built near Thengaipatnam in Kanya-kumari, Perumanal and Uvari of Tirunelveli and Pettainagar-Periyakuppam of Cuddalore and Nemili near Chennai had aggravated the sea erosion in all the coastal districts and mineral resources have been exploited in large tracts”, confirmed Raju.
The Pondicherry beach is a clear example of beach erosion and national level study papers submitted to Union ministry of earth sciences shows that 40 per cent of the Indian coast is under threat due to global warming and sea erosion, said Mr Probir Banerjee, president, Pondycan, an NGO working on beach restoration in the union territory. The moment any artificial intervention is done to the coast, three majors concerns will follow — loss of beach, depletion of fish catch and seawater intrusion affecting the water aquifer. Now both Pondy and Cuddalore are facing seawater intrusion, he added.