The shutters of the Idukki Cheruthoni dam were opened on a trial basis at 12.30 pm on Thursday.
A meeting chaired by Chief Minister Pinarayi Vijayan on Thursday had decided to open one of the five shutters of the Idukki dam.
Shutter number 3 was lifted by 50cm and is expected to be opened for four hours, In the trial run, approximately 50 cubic metres of water will be released per second.
The decision to run the trial was held after the water level in the dam reached 2398.88 feet.
Officials have informed that the people living in the valley of Cheruthoni dam and in an area of 100 metre near Cheruthoni and Periyar rivers should be cautious. People have been warned against fishing, bathing and taking selfies in the river and dam premises.
It was in 1992 that the dam was last opened.