Tamil Nadu

TN received 53 per cent excess rain in 2015

Huts along the Adyar river near Saidapet bridge were submerged in Chennai floods recently. Photo: G. Sribharath  

The devastating rains that created havoc in Chennai and neighbouring districts earlier this month, was due to slow movement of weaker systems present over Bay of Bengal, which subsequently led to 53 per cent higher rainfall than the average, the weather office said on Thursday.

“As the clouds above the sea were normal, the weaker systems like trough, low pressure moved slowly bringing copious rainfall,” Regional Meteorological Centre Director S.R. Ramanan told reporters here.

He was giving a detailed analysis on the rainfall registered during the North East Monsoon that normally sets in during the October-December period for Tamil Nadu and neighbouring Puducherry.

“On an average, Tamil Nadu and Puducherry receives 44 cm of rainfall during the North East Monsoon. This year the rainfall recorded is 68 cm in these three months, which is 53 per cent more,” he said.

In 2013, rainfall received was 33 per cent less compared to average rainfall. In 2014, October received heavy rain but there was no rain in the next two months. “But, in 2015 the rainfall received in Tamil Nadu and Puducherry was very good and it was similar to 2005,” he said.

Giving statistics, he said Kancheepuram district registered the heaviest rainfall — 183 per cent higher at 181.5 cm as against average rainfall of 64 cm in October-December period.

Tiruvallur district recorded 146 cm compared to average 59 cm of rain while Chennai, which normally receives 79 cm of rainfall, recorded 160 cm, 104 per cent above average, he said.

To a query, he said if the weaker low pressure or trough moved towards Gulf of Mannar region, south interior districts would also have received “record rainfall”. “Since the weaker systems were moving slowly or almost remained stationary, the coastal districts received heavy rainfall,” he added.

Due to heavy rains earlier this month, Chennai and neighbouring districts were inundated. According to the government, 345 persons lost their lives in rain-related incidents during the period while many were rendered homeless.

Asked if the North East Monsoon may be considered inactive following conclusion of the season from today, he said, “Even today Pechchiparai in Kanyakumari district received 4 mm of rainfall. But if there is no rainfall for four to five days, we may say the monsoon has ceased.”

He said the formation of El Nino in Pacific Ocean, an abnormal weather pattern that causes warming of Pacific Ocean, was also one of the reasons that brought heavy rain in December in coastal districts.

1 The floods in 1943 were historic and damaged Cooum river very badly. Based on the Er.A.R.Venkatachary's Report the government had improved the Cooum river and provided a sand pump at the river mouth of sand bar.
2 In 1978, there was catastrophic flooding in Chennai and this time it was the turn of the Adyar river. Earlier, Er.P.Sivalingam Committee had given its recommendations for prevention for further damages from floods and recommended schemes to be implemented in the short and long terms.
3 The floods that occurred in 2005 were one of the worst in living memory. Although several ameliorating measures have been implemented they have failed to provide total relief to Chennai citizens.
4 Most of the existing waterways are silted and their flow channels and banks are obstructed with encraochments and structures. So is the case with reservoirs and tanks. Secondly several of the areas under tanks and their anicuts have been developed as residential neighbourhoods over the years.
5 T.Nagar, Nungambakkam, Vyasarpadi are instances in this respect. The Taramani area has been developed as an institutional area. Thirdly the geological structure particularly in the south-west is not conducive to water infiltration.

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Printable version | Jun 20, 2021 1:02:06 AM | https://www.thehindu.com/news/national/tamil-nadu/tn-received-53-per-cent-excess-rain-in-2015/article8049979.ece

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