Amid the worst drought Tamil Nadu is facing in 140 years, an experiment to prevent evaporation loss in a water body was carried out under full media glare. Led by Minister for Cooperation Sellur K Raju and Madurai Collector K Veera Raghava Rao, the team used thermocol sheets held together by cellophane tape to try and partly cover the Vaigai dam's current storage area, which measures 10-12 hectares.
But the wind and the waves refused to accept the cover and the sheets came back to the shore in no time. After repeat attempts produced identical results, a bright spark suggested the use of a coracle to place the sheets in the middle of the water body. That was tried out as well, but the sheets washed back to the shore faster than the coracle could return.
The experiment was as hilarious as it was juvenile. But the concept of using thermocol to cover a water body is not exactly new, scientists have already tried it in small tanks. Years ago, the Rajasthan Agriculture University did experiments with floating materials such as vegetable oils, wax, wheat husk, paddy husk, wooden blocks, saw dust and thermocol boards. In Chennai's Poondi and Cholavaram reservoirs, cetyl alcohol emulsion was used in the 80s to reduce evaporation.
There is already a large body of work on the science to reduce evaporation. Vaigai dam alone loses 1.2 mcft water through evaporation each day, Collector Rao pointed out to justify the experiment. His concern is well taken, but had he consulted scientists, they might have told him that thermocol would perhaps work only in small tanks where the wind and wave factors are not pronounced. And for God's sake, find other means to bind the sheets, not cellophane tape!But full marks to minister Raju's spirit of inquiry and scientific temper. He took criticism on his chin and was willing to learn. Last heard, his aides were looking to procure thicker thermocol sheets to repeat the experiment.