Thiruvananthapuram: The India Meteorological Department (IMD) on Friday issued a 'Yellow' alert for seven districts in Kerala as the state braces for more rains with a cyclonic circulation persisting over coastal southern Tamil Nadu.
The IMD predicts the cyclonic circulation would bring widespread rainfall across Kerala over the next few days.
As trough is seen from the cyclonic circulation above south coast of Tamil Nadu to the Karnataka coast in the middle east Arabian Sea, thundershowers would continue in the state till October 26. Heavy rains is likely in isolated places, the Met department said on Friday.
Seven districts — Pathanamthitta, Kottayam, Idukki, Palakkad, Malappuram, Kozhikode, and Wayanad — are on yellow alert on Friday.
The IMD has also sounded Orange alert for Kottayam, Idukki, Palakkad, and Malappuram on Monday.
A Red alert indicates heavy to extremely heavy rains of over 20 cm in 24 hours, while an Orange alert denotes very heavy rains from 11 cm to 20 cm of rains. A Yellow alert means heavy rainfall between 6 to 11 cm.
The Met department has also predicted heavy rains in hilly areas in the state due to the cyclonic circulation, which is expected to last for next two days.
Twelve teams of the National Disaster Response Force (NDRF) are currently deployed in various districts. Three teams each of the Army and the Defence Security Corps (DSC), two IAF helicopters and a naval helicopter are on standby.
Alert sounded in dams
A red alert has been sounded in Kakki, Sholayar, Pondumi, Peringalkuthu, Kundala, Kallarkutty, Irattayar, Lower Periyar, and Peechi dams. Idukki-Cheruthoni, Mattupetty, Chimmini, Chulliyar, Malampuzha, Mangalam, and Meenkara dams are under Orange alert.
Two shutters of the Idukki-Cheruthoni dam have been closed on Friday as the water inflow to the reservoir decreased. This comes just three days after three shutters were lifted in view of heavy rains.
The water level of Cheruthoni dam had touched 2398.30 ft at 10 pm on Thursday. However, with the release of water and reduced inflow, the water level again came down to 2398.24 ft on Friday. It was 2398.08 ft on Tuesday when three shutters were raised as a precautionary measure.
After a brief lull, heavy rainfall, accompanied by thunderstorms and lightning, lashed several parts of Kerala on Thursday.
Meanwhile, the water level in Mullaperiyar dam rose to 135.10 ft on Thursday. The water will flow through the spillways when it reaches 136 ft. If the shutters are opened, the water from Mullaperiyar dam will flow through the Periyar river and reach Idukki dam.
Rule curve of three dams modified
Meanwhile, the state government has raised the rule curve of three dams under the state electricity board. A rule curve or rule level specifies the storage or empty space to be maintained in a reservoir during different times of the year.
While the rule curve of Idukki dam has been raised to 2399.31 ft from 2398.86 ft, Idamalayar dam and Kakki dam's new rule curves are 167 ft (previous rule curve - 166.8) and 979.84 ft (978.83 ft).
The aim this is to ensure maximum storage based on water availability, dam capacity and safety. The rule curve is raised during the rainy season and lowered proportionally to the drought in the summer.
The rule curve is raised 3 times a month from June to November. Idukki will be raised to 1459.55 ft by the end of November. Meanwhile, the rule curve of the Banasura Dam will remain at 775.6 ft.
