Shutter 3 of the Cheruthoni dam of the Idukki reservoir was opened at 10 a.m. on Thursday following an increased inflow into the Periyar following the opening of the Mullaperiyar dam and heavy rainfall in the Idukki high ranges since Wednesday night.
Earlier, Idukki Collector Sheeba George said a shutter of the Cheruthoni dam would be raised by 40 cm to a metre to release around 40 cumecs of water and those living on the riverbanks should adopt precautionary measures. She banned fishing and tourism activities in the Periyar and warned people against bathing or crossing the river.
The shutter was opened to regulate the water level as it was nearing the upper rule level of 2,400.03 ft. The water level reached 2,399.44 ft at 9 a.m. The opening of the dam shutter was synchronised with the water from the Mullaperiyar reaching the Idukki reservoir, said Water Resources Minister Roshy Augustine.
The water level in the Idukki dam has been at the red alert level for the past two days. The full reserve level is 2,403 ft. (The storage was 95.74% on Thursday, which was 88.86% on the same day last year).
At 8 a.m., two spillway shutters of the Mullaperiyar dam were opened to release water to the Periyar after the water level reached the upper rule curve level of 141 ft. At 10 a.m., two more shutters were opened. The average discharge to the Periyar at 5 p.m. was 1,544 cusecs.
Tamil Nadu was drawing water at 2,300 cusecs while the average inflow was 2,493 cusecs. The water level rose suddenly to the upper rule level following heavy rain in Periyar village from Wednesday night.
The Mullaperiyar dam was last opened on October 29. The Cheruthoni dam has been opened for the third time this year within a period of two months. After the opening of a shutter, the water level was steady at 2399.46 ft by evening in the Cheruthoni dam.
After the opening of the spillway shutters, the water level in the Mullaperiyar dam receded to 140.95 ft at 5 p.m. The present rule curve levels fixed by the Central Water Commission are applicable to the Idukki and Mullaperiyar reservoirs till November 20.
