Till a few years ago, Santhosh and other villagers of Sulerikattukuppam in Nemmili panchayat off East Coast Road near Chennai spent several idyllic hours every day on the beach. Little did they imagine that a desalination plant in neighbouring Nemmeli would deprive them of the vast, sprawling beach, the only spot for recreation in the vicinity.
Sea water intrusion caused by the construction of the desalination plant has claimed a stretch of coast up to half a kilometre inland in Sulerikattukuppam. There is no beach any more and hundreds of fishermen have lost their livelihood.
"Fishermen here were left with no option, so they joined construction companies as painters and welders for a meagre pay," Santhosh said. The state government built seawalls after the residents held several protests last year.
The government was till recently paying each of the fishing families in the village Rs 2,000 a month as relief. Sulerikattukuppam is not the only victim of erosion due to man-made structures along the coast.
A study by the National Centre for Sustainable Coastal Management (NCSCM) of the Union ministry of environment and forests reveals that a 41.4% of the 993.39 km long coast of Tamil Nadu is exposed to erosion.
Any man-made construction that projects into the sea, such as a port or breakwater, obstructs the normal movement of sediments including sand and gravel along the coastline, said B R Subramanian, project director Integrated Coastal and Marine Area Management.
"This leads to erosion on one side of the construction and an accumulation of sand on the other," he said. Tamil Nadu has 26 ports, both existing harbours and those under construction. Subramanian said the coastal assessment study by NCSCM is the first research on erosion along the coast and will help authorities evolve policies to take corrective action in areas that have been affected by severe attrition of the shoreline.
The study has used photographs and satellite images of the coastline between 1972 and 2010. The shoreline of six of the state's 13 coastal districts has been hit by erosion, with the situation being particularly bad in Villupuram.
Experts say coastal villages have been affected by erosion after Puducherry constructed a port. Stretches of coastline north of ports in Chennai, Ennore, Tuticorin and Nagapattinam have also been eroded. Along the eastern coast, waves approaching from the southeast cause the shifting of sediments, mainly sand, in a phenomenon known as littoral drift.
This occurs for nine months each year, causing sand to be pushed to the north. During the Northeast Monsoon, between October and December, the waves approach from the northeast, pushing sand from the north to the south.
Any construction on the coast interferes with this natural process and causes erosion. The littoral drift in Ennore is 0.35 million cubic metres a year, the highest on Tamil Nadu coast. Seawalls built for about 31km along the coast in Tamil Nadu have protected the shoreline from erosion, but not by much.
At least 33% of the Nagapattinam coast and 15% of Kanyakumari are covered by groynes and rubble-mound seawalls, but these districts still face the risk of erosion. Experts say alternate methods should be tried to protect the coast.
But V Sundar, of IIT-Madras' department of ocean engineering, said there have been lapses in coastal protection. "No authority seems to be monitoring coastal protection work," he said. "Port developers get clearances from the ministry of environment and forests without commitments to protect the coast from erosion."