Chennai, April 22 (IANS): The Tamil Nadu government’s attempt to cover the water stored in Vaigai Dam in Madurai with thermocol sheets to prevent evaporation shows the officials lack of knowledge about water cycle and ecology, said an environmental activist. On Friday Minister for Cooperation Sellur K Raju inaugurated the programme to cover the vast sheet of Vaigai Dam water with thermocol sheets at an outlay of Rs 10 lakh. According to an official in the Public Works Department (PWD), the idea was to spread the thermocol sheets on 200 sq metres of water surface on a trial basis to prevent water evaporation. The official said the idea is to study the plan first and if the results are positive then the plan could be expanded. However soon after the thermocol sheets taped together were laid on the water surface they reached the shores and some even broke. “The plan shows the lack of scientific knowledge of the water cycle. Water evaporation is a natural process and is part of water cycle. Why should one try to prevent the natural process,” G. Sundarrajan, an environment activist with Poovulagin Nambargal, a non-governmental organisation (NGO) working in environment area. “Secondly thermocol is harmful if ingested. If fishes or birds eat the thermocol then it will cause major harm to them,” he added. He said floating thermocol in the water stored in a dam and expecting them to stay at one place is foolish. Officials said the water stored in the dam is the main source of drinking water for Madurai city and preventing the 1.2 mcft (million cubic feet) evaporation loss per day is important.