For the first time in 26 years, the Idukki dam was opened again as the water levels rose to just below 2399 feet in the reservoir, just 4 feet below its full capacity.
At 12:30 pm on Thursday, one shutter of the Cheruthoni dam was opened 50 centimetres to let the water out.
A statement released by Idukki Collector instructed all those living 100 metres along the stretch of the Periyar near the dam to relocate to safer spots.
Residents living along the lower areas of the river have been relocated to a location arranged by the village officer and their stay there will be taken care of, the release stated.
The authorities instructed residents to keep all their valuables and certificates safe and instructed people to not crowd the banks of the river.