The last time it was opened was in 1992 when water level crossed the maximum height of the dam. Twenty-six years later, one of the gates of the Idukki Dam in Kerala’s Idukki was opened once again as water rose to dangerous levels and incessant rains flooded parts of the state killing 20.

On Thursday, the Kerala government ordered the opening of gate number 3, known as Cherutheni shutter, to reduce the accumulated water in the dam.

Reports say that the water level had crossed 2398.80 feet against full capacity of 2403 feet. About 50 cubic metres of water every second flowed out as the gate was lifted by just 50 cm.

Residents living in the vicinity of the dam and along the Periyar river were warned before the opening of the gate since there is a risk of flooding.

The tallest arch dam in the country, Idukki Dam was once opened in 1981 in a similar situation.

Kerala has been receiving heavy rainfall since June. Chief Minister Pinarayi Vijayan postponed Saturday’s annual Nehru boat race in Alappuzha in view of forecast of heavy showers.

The deaths include 11 from Idukki, six from Malappuram, two in Kozhikode and one in Wayanad.

Speaking to the media, Vijayan said rains had caused extensive damage to life and properties across the state. “We have sought six additional teams of National Disaster Response Force,” he added.

Read More: Kerala rains leave 20 dead, Nehru boat race put off

“Since more rains are forecast, as a matter of abundant caution, it has been decided to postpone the upcoming Nehru boat race on the Punnamada lake. The new dates will be announced by the organisers,” said Vijayan.

“Since this episode has led to widespread loss and destruction, the requirement of money is there and we call upon all who are willing to donate. They can do it to the Chief Minister’s Fund,” Vijayan said.

Four shutters of the Idamalayar dam were also opened in the morning. The opening of the dam shutters resulted in an increase in the water level in the Periyar river.

As a precaution, the Cochin International Airport Limited, which is situated close to the Periyar river, stopped the arrival operations on Thursday and diverted all incoming flights to other destinations, anticipating a possible inundation in the airport area.

A special monitoring cell has been opened in the state secretariat and all 14 district collectors had been directed to open one each as well.