Novel idea gone with wind at Vaigai dam

Officials of the Public Works Department (PWD) decided to float thermocol sheets on water, said to be the first attempt in the country, to minimise loss of water due to evaporation in Vaigai dam. However, their attempt failed as heavy winds blew the sheets away within a few minutes of being placed on top of water.   Officials thought that the thermocol sheets would block the Sun rays. But, what happened was entirely opposite. 

“As soon as the sheets were placed on the water surface they moved fast and reached the end of the dam, even before the workers on boats reached the banks. Meanwhile, some of the sheets began to absorb water and disintegrated into small balls. It is said that thermocol not only harms the environment, but also causes death of fish. 

With little concern about the harmful effects of thermocol, officials had spent a whopping Rs10 lakh on the project. Minister for Cooperation, Sellur K Raju, said that the officials were inspired by such experiments that were carried out abroad. He said the sheets flew because they were light and explained that thicker sheets would prove to be effective in future.  Madurai Collector K Veera Raghava Rao explained that this was just an experimental project. Thermocol sheets were placed on just 200 square metres out of total 15 hectares. 

“We have also planned to use plastic sheets and balls to minimise evaporation. In addition to this, water lost due to evaporation from the dam will be monitored every day. Only then the effectiveness of the experiment could be gauged.” When the environmental hazard of placing thermocol sheets on the water was pointed out, he denied that they could harm fish. 

To a question about why permanent steps were not being taken to prevent evaporation, the Collector replied that they were trying out various measures and the most successful method would be implemented.  

An official from Theni district, on condition of anonymity, said that so far, officials in foreign countries have used thermocol sheets only on ice and not on running water. This experiment was a farce, but ministers and officials were not ready to heed any suggestion or advice.    

The Vaigai dam is the major source of water to Madurai district and drinking water projects of the Madurai Corporation, besides the Andipatti-Sedapatti integrated drinking  water scheme. Six mcft is required for both the  drinking water projects per day and at present there is only 162 mcft in the dam. Every day, on an average, the dam loses 1.2 mcft due to evaporation.