The Kopili plant

Shillong, Nov. 18: Experts have called for scientific means to reduce the highly acidic nature of the reservoir water, which is hampering the power generation capacity of the Kopili hydroelectric plant in Assam.

The 275MW plant is located in the Kopili river at Umrangsu in North Cachar Hills district of Assam, adjacent to the Jaintia Hills in Meghalaya. It was the first project taken up by the North Eastern Electric Power Corporation (Neepco) after it came into existence in 1976.

Neepco, which organised a meeting in Shillong today, had brought experts in the field of geology, hydrology, environmental science, hydroelectric engineering and machine manufacturers from various parts of the country to discuss the problem of acidic water in the reservoir.

According to experts and scientists, it is because of the unscientific coal mining in the adjacent Jaintia Hills district that the water at the reservoir is turning acidic.

The Neepco officials also pointed out that the life span of the reservoir might be reduced if the acid content of water is not tackled at the earliest.

Chemistry professor of Gauhati University K.G. Bhattacharya said the acidity of the reservoir water had seriously affected the performance of the plant with severe corrosion of the submerged parts of the generating units.

The acid effect on the power plant equipment and civil structures, environmental degradation in the upper catchment areas and its effect on the downstream stretch of the Kopili is a cause of concern, he said. Highlighting the urgent need to use better quality steel and acid-resistant polymers, he said the acidity was the result of rampant coal mining in the Jaintia Hills district of Meghalaya.

According to him, the Central Pollution Control Board has some guidelines on scientific methods mining of coal. But these are seldom followed by the coal mine owners in the Jaintia Hills because of the peculiar land tenure system in Meghalaya where the mines are owned by the individuals, not the government.

He said Neepco should identify all the small streams which feed the Kopili, to assess the acidic content and address the issue.

The head of the department of environmental science, Nehu, O.P. Singh, said if the pH level was less than 3, the water could not used even for agricultural purposes. The pH level of the Kopii reservoir is 4 and pH less than 7 is considered as acidic.

Singh said the condition was unsuited for the survival of fishes too.

Director of New-Delhi based Central Soil and Materials Research Station Murari Ratnam said the annual loss because of less power production at the Kopili plant would be around Rs 100 core.

He said power generation at the plant was severely affected because of the unprecedented wear-and-tear and breakdown caused by the acidic water in the reservoir.