IDUKKI: Three of five shutters of Cheruthoni dam of Idukki reservoir were raised on Sunday to release 100 cumecs (around 3,531 cusecs) of water. The water will be released in a phased manner until Monday morning. This is the 11th time since the dam’s commissioning in 1976 that the shutters have been raised.
Meanwhile, six out of 10 open shutters of Mullaperiyar dam were further raised to 50cm from the earlier 30cm at 10am on Sunday due to heavy inflow. Discharge of water was increased to 3,232 cusecs. Water level in the dam was 138.4ft against the permissible level of 142ft. The 10 shutters were opened on Friday, August 5.
Though there was no flooding owing to the raising of Cheruthoni dam shutters, around 75 families in the flood-prone area of downstream Cheruthoni were asked to shift to relief camps if water in Cheruthoni river rose.
“The dam shutters were raised considering the possibility of heavy rain in the coming days. The controlled release of water will regulate its level in the dam and prevent a flood downstream,” water resources minister Roshy Augustine told reporters. The heavy rain lashing the district for the past one week and the raising of Mullaperiyar dam shutters caused water level in Idukki dam to rise.
The upper rule curve (level to be maintained in a reservoir at different times of the year) of Idukki dam for August 10 was set at 2,383.53ft against the full reservoir level of 2,403ft. On Saturday, it crossed the red alert level and reached 2,382.53ft at 7.30am, necessitating the raising of shutters on Sunday.
Three warning sirens were sounded from 9.50am on Sunday before shutter 3 was raised to 40cm to release 50 cumecs of water. It was raised to 120cm by 4pm. After water reached 2,384.46 ft at 2pm, shutters 2 and 4 were raised to 40cm, while shutter 3 was lowered to 75cm to collectively release 100 cumecs of water.
Steps taken to ensure people’s safety, says Roshy
Water level in the Periyar river was 793.29m, 1m below the warning level of 794.2m, before the shutters were raised. “Since the level is lower than the danger mark of 795m, there is no possibility of severe flooding downstream.
Nonetheless, officials of the revenue, local self-government and other departments have taken all steps to ensure safety of people living downstream,” Roshy said. Cheruthoni resident Latha Siby said the release of water from Idukki had not led to flooding in Cheruthoni town and nearby areas. Sunday marked the 11th time that the shutters of Idukki dam were opened since its commissioning in 1976.
They were first raised in October 1981 to release 32.88 cumecs of water. They were raised twice again between October and November to release 23.42 cumecs and 9.46 cumecs of water, respectively. The shutters were raised twice again in 1992, releasing a total 78.57 cumecs of water.
After staying closed for 26 years, the shutters – all five of them – were raised in 2018 to release 1,068.32 cumecs of water. In 2021, the shutters were raised four times within a span of three months from October, and a total 75.06 cumecs of water released.