PWD’s ‘novel idea’ to contain evaporation in Vaigai dam ridiculed on social media

With the Public Works Department’s ‘novel’ idea of floating thermocol sheets to contain evaporation in the Vaigai dam failing miserably, Minister for Cooperation ‘Sellur’ K. Raju has now said that the administration was examining the possibility of using plastic shade balls for the purpose.

The Minister, who inaugurated the initiative on Friday, had attracted widespread ridicule on social media for experimenting with an ill-thought-out idea. He said during the inauguration that ₹10 lakh had been allocated for the initiative to contain water evaporation, which many felt to be an inflated estimate.

The PWD set out thermacol floats in the Vaigai dam in an effort to prevent water evaporation to conserve water in a drought year, but the sheets were blown off in the wind.

Heavy wind blamed

When contacted, Mr. Raju told The Hindu that the thermocol idea experimented by PWD failed due to heavy wind. “Since Madurai is staring at a drinking water crisis with the water in Vaigai dam expected to be available only for around five weeks, we need to save water in all possible manners, including prevention of evaporation loss,” he said.

Officials were analysing the possibility of floating shade balls, made from a type of plastic, which have been tried in some foreign countries, including the U.S.

On Friday, when the media asked him about the rationale behind using thermocol sheets, which could cause environmental damage, Madurai Collector K. Veera Raghava Rao also indicated that the administration might try plastic balls if the thermocol experiment failed. However, a senior PWD official, speaking on anonymity, said it may not be that easy to experiment with shade balls. “They were primarily intended to prevent UV rays from catalysing chemical reactions in chlorinated water, which could result in formation of harmful chemicals,” he said.

“Moreover, covering the present water spread area of around 12 hectares would require few crores of these balls,” he pointed out.

He pointed out that PWD officials were ill-prepared in trying out thermocol sheets experiment. “They should have at least used thicker sheets and had a mechanism to contain them to a particular area,” he said.

M. Muthupandian, Executive Engineer, PWD (Periyar Vaigai Division), who oversaw the experimentation with thermocol, said that they were planning to try the idea in 200 square metres. He said 1.2 mcft of the nearly 160 mcft of water presently available in Vaigai dam was getting evaporated every day.