THOOTHUKUDI: Following predictions of heavy to extremely heavy rainfall owing to the cyclonic storm Burevi, the southern districts of Tamil Nadu are on high alert. The India Meteorological Department (IMD) had forecast that the cyclone is expected to make landfall between Pamban and Kanyakumari during December 3 night or early on December 4 morning.
It may be noted that south Tamil Nadu is bracing for a cyclone after 20 years. The last cyclone to hit south Tamil Nadu was in 2000. Major cyclonic storms to strike the southern Tamil Nadu coast were recorded with landfall at Ramanathapuram in 1978, Tiruchendur in 1992 and Thoothukudi in 2000. The Ockhi cyclone, which devastated the Kanyakumari coast in December 2017 crossed over the sea 80 km south of Kanyakumari.
The IMD began naming the cyclones only after 2004.
Red alerts are issued when extremely heavy rainfall of above 20.4 cm is expected. Heavy rainfall alerts are issued when it's expected to clock 64.5 mm to 115.5 mm, and very heavy rainfall if it's between 115.6 mm and 20.44 mm.
Highest rainfall in the past
Some pockets of Thoothukudi had recorded extremely heavy rainfall in a single day and those records have not been broken for several decades.
Kulasekarapattinam had recorded a maximum of 31.5 cm of rainfall on December 4, 1940, while Tiruchendur received 28 cm on December 6, 1997, followed by Keelarasaradi with 24.4 cm on December 16, 1946, Sathankulam with 22 cm on November 3, 2018, Kayalpattinam with 21.5 cm on November 18, 2020 and Kayathar with 21.3 cm on November 9, 1925. Thoothukudi town received 20 cm on March 14, 2018 surpassing its former record of 18.8 cm registered on December 3, 1955, according to official data available.
According to amateur weatherman T Raja of Tiruchendur, the 1992 cyclone which made landfall through Tiruchendur with a gusting storm of 100 kmph, led to extremely heavy rainfall across southern districts and wreaked havoc in both Thoothukudi and Tirunelveli districts. The areas closer to the Western Ghats -- Ambasamudram, Papanasam, Servalaru, Manimutharu -- recorded 32.1 cm, 31.0, 21 cm and 26 cm of rainfall respectively on November 13, triggering high influx of flood water into the dams and the river was in full spate, he said.
On November 13, 1992, the Public Works Department (PWD) released at least 2,04,273 cusecs of water into the Thamirabarani from Papanasam dam, which caused a deluge along the river banks in Thoothukudi and Tirunelveli districts. As many as 17 persons belonging to Thiruvalluvar Nagar in Papanasam of Tirunelveli district were swept away by the river, while 10 buses were submerged in Tirunelveli bus stand and hundreds of cattle were washed away. The Authoor village located on the right bank at the tail end in Thoothukudi was flooded and hundreds were shifted to safe places, said sources.
Raja, who is also professor at a private college, stated that the cyclonic storm Burevi is more likely to hit the shore between Thursday night and Friday morning. The cyclone would be centred between Ramanathapuram and Thoothukudi districts and expected to shower extreme heavy rainfall across Thoothukudi, Tirunelveli, Tenkasi, Kanyakumari, Ramanathapuram and Sivaganga districts. Some of the old rainfall records of Thoothukudi might be surpassed when the cyclone makes landfall, he said. Usually a dry and parched district, Thoothukudi receives ample rainfall during red alerts, he added.
Meanwhile, PWD officials say that a catastrophic incident is unlikely to be repeated this time despite the extreme heavy rainfall predicted amid Cyclone Burevi.
Speaking to The New Indian Express, Thamirabarani PWD Executive Engineer Annadurai said the three major dams in the Western Ghats have a water deficit as Papanasam holds 80 percent water, while Manimutharu and Servalaru dams hold only 60 percent of their full capacity. Papanasam and Servalaru have received inflow of 822.41 cusecs, while Manimutharu got only 128 cusecs due to poor rainfall, he added.
As of now, Papanasam stores water to 124 feet out of its total depth of 143 feet, Servalaru also stores 124 feet of its full capacity of 156 feet and Manimutharu holds water to 96.30 feet of its depth of 118 feet, he said.
Stating that the very heavy rainfall will raise water levels at dams to the brim, Annadurai said the possibility of floods along the river valley is low as the downpour will continue for only 24 hours.
The official made it clear that the situation along the Thamirabarani river is under control and comfortable given the levels of the dams. The Thamirabarani at Maruthur anaicut in Thoothukudi district releases 1500 cusecs of water.
Nine irrigation channels branching off from Thamirabarani including seven in Tirunelveli are closed now, while two other channels - East canal (Keezhakal) and West canal (Melakal) in Thoothukudi district are opened for irrigation purposes, he said.
The Srivaikuntam anaicut, the last water harnessing structure across the Thamirabarani, holds 70 percent of its total capacity of 124 million cubic feet. The Srivaikuntam anaicut which has 8 feet depth currently holds 6.3 feet of water. The water overflowing from Srivaikuntam anaicut would emerge into the Gulf of Mannar in the Bay of Bengal, Annadurai said.