IDUKKI: Mullaperiyar and Idukki dams are facing a higher risk than ever this monsoon. Both the reservoirs are nearly full at the same time of the year. The Idukki reservoir had almost reached its full capacity during the southwest monsoon this year. Water level has been brought down to 2,388.36 feet above the mean sea level by increasing power generation.
The water level in the dam is only 16 feet away from reaching full capacity. Earlier, in July 1991, the water level had reached the same level.
The power generation at Moolamattam power station on Wednesday was at a high of 13.246 million units (till Wednesday 7 am). The catchments of both the reservoirs have been experiencing heavy rain for the past few days. The catchment areas of the Mullaperiyar dam — Periyar and Thekkady — received a rainfall of 26 mm and 22 mm respectively, while Idukki dam received a rainfall of 94 mm rainfall on Wednesday.
Tamil Nadu has reduced the intake from Mullaperiyar from 2,300 cubic ft per second to 2,100 cubic ft (6 am on Wednesday) to raise the water level to 142 ft. This can increase inflow of water, which flows down to the Idukki reservoir.
The full reservoir level of the Idukki project is 2,403 feet (732.62 metres) above the mean sea level. The risk can be reduced by starting the release of water before it rises to the full reservoir level at Idukki and keeping the generation levels up. “The water level can safely go up to the maximum reservoir level of 2,403 feet. However, problems compound when something unexpected like blockage of spillways or disruption of power generation occurs,” said an official.
The problem will be beyond management if the 110-year-old Mullaperiyar dam fails when the Idukki reservoir is full. Overtopping of Idukki dams will be a certainty in such an event. Theoretically, a concrete gravity dam like Cheruthoni will topple if water level exceeds the maximum reservoir level. However, the officials monitoring the Mullaperiyar dam said the water level in the Mullaperiyar reservoir was holding steady at 135.40 ft on Wednesday morning. If the rain continues the water level may raise further.