Kumily: A total of 2,200 million cubic feet (mcf) of water from the Mullaperiyar dam was diverted to the Vaigai dam, near Andipatti, in the Theni district of Tamil Nadu, as the water level reached 137.10 feet on Monday.

A total of 1800 mcf of water was released through four penstock pipes and 400 mcf through the Erachipalam route on Sunday. In case of emergency, Tamil Nadu can now take away only an additional 300 mcf of water. Then, the final option left is to open the shutters of the spillway of the Mullaperiyar dam and release water to the Periyar river in Kerala.

(A penstock is a pipe that delivers water to hydro turbines and sewerage systems. It also denotes a sluice or gate or intake structure that controls water flow.)

Meanwhile, there was a drastic reduction in the inflow of water to the Mullaperiyar dam since there was no rain in the catchment area of the dam on Sunday.

Since the intensity of the rain has come down, Tamil Nadu expects to maintain the water level in the dam below 136 ft. But if the northeast monsoon (or Thulavarsham) strengthens, the estimate of Tamil Nadu may go awry.

(Vaigai dam is built across the Vaigai river near Andipatti in Tamil Nadu.)

Protocol to release water

As per the protocol in place to release water from the dam, Tamil Nadu issued the first alert to Kerala when the level reached 136 ft on Saturday night. Subsequently, the second alert would be given at 138 ft, the first warning at 140 ft and second warning at 141 ft. When the level reaches 142 ft, shutters of the dam would be lifted.

According to the order of the Central Water Commission, Tamil Nadu, which is in charge of the dam, can maintain a water level of 142 ft two times a year and should raise the shutters only if the level touches this maximum mark.

Previous instances of hitting benchmark

The water level in the dam had touched the 142-ft level three times earlier after the Supreme Court of India allowed Tamil Nadu to store water up to that level.

The water level reached the 142-ft benchmark on November 21, 2014, December 6, 2015 and August 15, 2018. The earlier records suggest that the water level in the dam had breached the permissible limit of 142 ft during the "Thulavarsham".

Kerala official reviews situation

Idukki Revenue Divisional Officer (RDO) M K Shaji visited the Mullaperiyar dam site and reviewed the situation. He said there was no cause of panic right now.

An awareness campaign to allay the apprehension of people over the safety of the dam was undertaken in areas such as Vikas Nagar, Injikkad Attoram, Manjumala Attoram lying on the banks of the Periyar river. These areas within the Periyar Village located in Peerumade Taluk of Idukki district in Kerala.