Thrice in total, the floodgates of Cheruthoni had to be opened; twice during the northeast monsoon (October to December) of 1981 and 1992 and once during the 2018 Kerala floods. The first time was in 1981 (when the shutters were repeatedly opened and shut between 29 October and 13 November) and the second time was in 1992 (when they were kept open for 12 days from 12 to 23 October) and recently during the great flood of 2018 from 9 August 2018 to 7 September 2018, all 5 shutters were opened while all 14 districts of kerala were put under Red Alert with heavy disaster creating destruction all over kerala. On the first 2 occasions, the water level in the dam touched the brim only when the storage built up during the southwest monsoon (June to September) was augmented by the inflow received immediately afterwards following heavy downpour early in the northeast monsoon. On 9 August 2018, after a gap of 26 years, owing to continuous downpour of the southwest monsoon, the floodgates of dam in Idukki was opened. This was the first instance of water being released from the dam during the southwest monsoon season and also the first time in history when all 5 shutters of the dam were opened since it was commissioned in 1976.