KOCHI: Major dams across the state are brimming after a week of torrential rain, but the government has vowed that there will not be a repeat of 2018 even if the rain continues. Idukki and Banasura Sagar dams will start controlled release of water from Sunday while Idamalayar and Kakki dams will open the floodgates in a couple of days.
A shutter of the Cheruthoni dam will be raised by 70cm at 10am on Sunday, releasing 50 cumecs of water from Idukki reservoir. The level in Banasura Sagar in Wayanad crossed red alert level on Saturday night. The dam’s floodgates will also be opened on Sunday.
Though the situation draws a parallel to the 2018 flood, there is no confusion among authorities as the introduction of rule curve has ensured space to store water and regulate release considering the flood level downstream. Rule curve is the parameter set by the central water commission to ensure enough storage in dams.
“Water level in major dams has reached the rule curve level. But there is no need to panic as we have enough storage space. Water will be released with restraint from Idukki and Banasura Sagar dams on Sunday ensuring that there is no flooding in downstream areas. The release will be regulated according to the inflow. The situation is under control,” said Electricity Minister K Krishnankutty.
Idamalayar dam storage crosses blue-alert level
The storage in Idamalayar, the second biggest dam in the state, has also crossed the blue alert level and the spillway will be opened on Sunday or Monday. Kakki dam is on orange alert level and water will be released in a couple of days. The Lower Sholayar has been kept open due heavy inflow from dams in Tamil Nadu.
The state rule curve monitoring committee headed by additional chief secretary for revenue and disaster management reviewed the situation on Saturday and obtained permission from the chief minister to release water from the Idukki reservoir. The decision has been taken considering the water level in Periyar in Aluva. “There is no comparison with 2018 floods as we are releasing only 50 cumecs of water from Idukki. In 2018, we released 1,500 cumecs of water. The rule curve has helped us regulate the water level at 80% leaving a flood cushion of 20ft in Idukki. Even if there is torrential rain, we can store up to 330MCM water in the reservoir and release it over a period of 10 days,” said KSEB assistant executive engineer James wilson, who is also a member of rule curve monitoring committee.
The upper rule curve level of Idukki for August 10 is 2,383.53 ft while the full reservoir level is 2,403 ft. In 2018, the water level had risen to 2,400 ft after which the KSEB had to release huge quantity of water. Meanwhile, Tamil Nadu has informed Kerala that the spill from Mullaperiyar may be increased to 5,000 cusecs on Saturday night as the dam is receiving heavy inflow. The water level in Mullaperiyar stood at 138.2 ft at 8pm and the inflow was 5,172 cusecs. Tamil Nadu has to reduce the water level as the rule curve for the period is 137.5 feet.
“The release of water from Mullaperiyar will not cause flooding at Vallakadavu and Chappath. We have to be cautious only if the spill crosses 10,000 cusecs,” said James Wilson. He said Tamil Nadu has regulated the water level in Parambikulam dam on Kerala’s request, considering the flood situation at Chalakudy. The Idamalayar dam issued a blue alert as water level has reached 161.79 metres, which is 79.62% of the storage capacity. The dam is receiving an inflow of 4.5 MCM. Idamalayar will open the shutters when the water level touches 163 metres.