With the IIT-Madras study on the opening of a new mouth at Pulicat lake nearing completion, the waterbody could soon get a fresh lease of life.
Due to silting up of the lake mouth, the livelihood of thousands of fishermen has been affected. They have been complaining of a drastic fall in catch and also a reduction in the depth of the lake that causes their boats to get stuck at various points.
Durai Mahendran of Tiruvallur Maavatta Paarambariya Aikiya Meenavar Sangam says fisherfolk, who were earning around Rs. 1,000 a day now manage to make just about Rs. 300 a week.
“Recently, the fisherfolk came together to engage earthmovers to remove sand from the mouth of the lake,” he says. According to ecologist P.J. Sanjeeva Raj, the mouth of the lake is its very heart.
“Unless there is tidal action, not just the mouth, but the lake too will get silted up. Tidal action is felt up to 12 km and will flush out the accumulated silt. Over the centuries, it has become shallower. In 1606, during the Dutch period, Pulicat’s average height was said to be 3.8 metres. The depth was such that Dutch ships were able to enter it. In 1953, the average depth reduced to 1.5 metres and now it is said to be just 0.5 metres,” he says.
The State government roped in IIT-M after repeated requests from fisherfolk. Professor R. Sundaravadivelu, from the department of ocean engineering at IIT-M, who had provided consultancy for opening up of the Chilka lake in Odisha, says an optimum location is being chosen based on a Bathymetry survey conducted along with the fisheries department.
Local fishermen have also been consulted. Training walls will keep the mouth open so fishermen can ply their boats throughout the year, he says.
S.A. Sannasiraj, also from IIT-M’s ocean engineering department, along with professor V. Sundar, is carrying out numerical model studies to finalise the configuration of the training walls at the mouth. The report is likely to be ready in a month.
The direction and height of waves and orientation of the shoreline are being studied to fix the alignment of the training walls. The direction of the waves will show how much the sediment will move, he says.