Kerala government has announced an Orange alert along the banks of the Periyar, with the water levels in the Idukki dam rising to 2395 feet on Monday night.
Rescue and relief teams have been deployed in both Idukki and Ernakulam districts to take over in the event of the dam's shutters being opened.
On Monday morning the water levels in the dam were at 2394.64 feet. Following steady rainfall, the water levels rose to 2395 prompting the government to issue the Orange alert. The alert, also known as Code Orange, is the second level of the three alerts issued by the Kerala State Electricity Board (KSEB) to warn those living close to the river.
The first - Green alert or Code Green - was issued when the water levels reached 2390 feet in the dam. Code Green warned those living along the river of the rising water levels.
The authorities will ideally open the dam shutters only after the third and final alert - Code Red - has been issued. The Red alert will be announced when the water levels in the reservoir reaches 2399 feet, leaving just 4 feet for the dam's capacity to max out at 2403 feet.
Once the water rises to 2400 feet, the authorities will be forced to open the dam shutters says Idukki Collector Jeevan Babu.
One of the largest arch dams in the continent, the 45-year-old Idukki dam has not been opened in the last 26 years. The Idukki reservoir has three dams - the main dam on the Periyar which holds the water and has no shutters, the Cheruthoni and Kulamaavu dams which channel the water for KSEB's 780 MW hydro-power project in Idukki.
The dam's shutters at Cheruthoni will be opened to release the water into the Cheruthoni river (tributary of the Periyar river) which will merge into the Periyar.
Plans to open the dam in a trial run before Code Red is announced, are being discussed by authorities. In the controlled trial run, the middle shutter of the 5 sluice gates of the Cheruthoni dam will be opened first. Following this, one of the shutters in the extreme left or right will be opened. The shutters will be opened for 10-15 cms and for a controlled period of 4 hours.
Rescue and relief teams deployed
Kerala CM Pinarayi Vijayan took to Facebook to announce the measures being taken in the event of the dam shutters being opened.
"...State Disaster Management Authority about relief measures. In Ernakulam's Aluva youth hostel, a team of National Disaster Response Force (NDRF) personnel have been deployed. In Thrissur and Idukki too, teams have been stationed," the post read.
Further, the Army, Navy, Air Force and teams of the Coast Guard have been alerted. As per the instructions of the State Disaster Management Authority, an Mi17V helicopter and an ALH helicopter have been readied for the purpose, according to the post.
"Four columns of the Navy and Air Force are ready to be deployed in case of crisis. In the event where the low-lying areas of Ernakulam district get flooded following the dam's opening, the coast guard teams have been instructed to undertake rescue operations with boats in the area," the post added.