The flood in Chennai on December 1 was a rare natural calamity and was not caused by any failure in the management of water releases from reservoirs.
Water discharge from the Chembarambakkam tank was steadily stepped up based on inflows and not all of a sudden. At night, the tank was ‘skillfully and judicially’ managed to moderate the flow in the Adyar River, said a statement issued by Tami Nadu Chief Secretary K Gnanadesikan refuting media reports that flooding of the Adyar River was due to improper management of water releases from Chembarambakkam tank, situated to the south-west of Chennai City in Sriperumpudur Taluk.
Adyar catchment full
The water level in the tank on December 1 was 5.08 ft with storage of 228 mcft. The rainfall in November 2015 in Chennai was 1,018 mm, which was the highest rainfall in November since 1918. All the tanks in the Adyar catchment reached full capacity and the surplus water flowed into the Adyar River.
Due to heavy rains, Chembarambakkam tank had copious inflows of water in the middle of November, and 18,000 cusecs was discharged into the Adyar River on November 17. On November 30, the water level was 22.05 ft with an inflow of 750 cusecs and outflow of 800 cusecs.
On December 1 morning, the water inflow started increasing and the water level in the Chembarambakkam tank was at 22.08 ft. As the inflow started increasing, the levels in the reservoir were carefully frequently monitored. Due to continuous heavy rains in the catchment, the tank started to receive heavy inflow in the afternoon, and continued till next day.
Based on the field situation, the engineers on the spot increased the outflow to 10,000 cusecs at 10 a.m., 12,000 cusecs at 12 noon and to 20,960 cusecs from 2 p.m. in the afternoon. This outflow was further increased to 25,000 cusecs at 5 p.m. and to 29,000 cusecs at 6 p.m. and maintained at that level till 3 p.m. next day and reduced gradually.
The maximum water level in the tank at 9 p.m. on December 1 was only 23.40 ft and had not reached the full capacity of 24 ft. The entire discharge was through the regulators and there was no uncontrolled discharge through the surplus weirs.
Engineers present at the Chembarambakkam tank site had taken the required decision based on the inflow into the reservoir. Similarly, water was being released from many other tanks and reservoirs, including Red Hills, Cholavaram and Poondi as a result of heavy inflow for which the local controlling officers took the decisions, he said.
Rebuts waiting for CM nod
“The allegation that they were waiting for instructions from the Principal Secretary, Public Works Department, and the Chief Secretary, and the imputation that the officers were awaiting the clearance from the Chief Minister are malicious and are canards not supported by the water release data of the reservoir,” he said.
The India Meteorological Department had only given an advisory of isolated extremely heavy rain but did not mention anything about 50 c.m. of rainfall as is being alleged in certain sections of the media, he said.
Flood warnings were given by the Collector, Chennai, and other officials in the media, and precautionary measures were taken up by the officials of the District Administration and Corporation of Chennai. The Collector of Chennai issued a first flood warning when the discharge reached 7,500 cusecs at 11.20 a.m. on December 1 and a second flood warning when the discharge reached 20,000 cusecs at 1.32 p.m. on the same day.
The warnings were telecast in television channels and FM Radio channels. There were at least 20 repetitions of the warning in the major regional channels, he said.
Immediately after the second warning, the Collector of Chennai and Corporation of Chennai, in close coordination with Chennai City Police, started the safe evacuation of people from low-lying areas. “Therefore, the allegation that the State Government had not given sufficient alert to the people is not true,” he said.
As torrential rains continued to lash Chennai and brought the city to a standstill on Friday, the scene evokes memories of the 2015 floods in Tamil Nadu that claimed around 347 lives across the state.
On Thursday, several coastal pockets of Chennai witnessed severe water-logging after rains lashed the city for a non-stop five hours following a low pressure on the Bay of Bengal near Sri Lanka. As a result of the rain in the state, schools in Nagapattinam, Kanchipuram, Thiruvallur and Chennai remained closed on Friday.
The state government has advised fishermen to be cautious while venturing into the sea in coastal areas of South Tamil Nadu and Delta districts. According to the Met Department, Chennai and Nungambakkam registered 18 cms of rain while Meenambakkam in the southern suburb recorded 14 cms, till 8.30 am on Friday.
Low lying areas in Chennai were flooded forcing people to wade through knee-deep water. S Balachandran, director of the Area Cyclone Warning Centre, warned moderate rainfall is expected in many places in south Tamil Nadu and a few areas in the north coastal parts of the state in the next two days.
Continuous rains bring back 2015 flood memories
DMK spokesperson Manu Sundaram slammed the Tamil Nadu government for not doing enough to stop a repetition of what took place during the 2015 floods. "Each week, the state government seems to be facing a new crisis. After just 12 hours of rains, Chennai city has brought back unhappy memories of 2015 floods. The government is ill-prepared and ill-equipped to handle another monsoon. Chennai and its residents may once again have to rise up to save each other," he told India Today.
Flooded streets in Chennai. PTI
In December 2015, the Jayalalithaa government faced flak over the staggering number of deaths and damage to property during the deluge. According to The Hindu, 347 people, 17.64 lakh cattle died and 1.16 lakh huts were damaged, forcing the late chief minister to write to Prime Minister Narendra Modi and declaring the Tamil Nadu floods as a "national calamity" and a "calamity of severe nature".
Following heavy rains on Thursday night, waterlogged streets made vehicular movement difficult with train services between St Thomas Mount and Kodambakkam station in Chennai stopped since 9.30 pm. Heavy traffic could be seen at the arterial Kathipara grade separator, Guindy intersection, Saidapet and till Velachery through the Raj Bhavan point, as per News18. Vyasarpadi amd Otteri areas in north Chennai, parts of West Anna Nagar in central Chennai and Madipakkam in south Chennai faced severe waterlogging as well.
Angry residents expressed their frustration and said the government had learnt nothing from horrific 2015 floods experience. According to the India Today report, Sunnambu Kolathur residents poured out on the streets to protest against the civic bodies as their homes also got flooded. "We have been regularly complaining to the authorities about lack of storm water drains and to ensure the area doesn't get flooded. The monsoon has just set in, and see our condition. What if it rains harder in the days to come," the report quoted Shivraj, a resident, as saying.
DMK working president MK Stalin also hit out at the E Palaniswamy-led government for negligence. He added that Monday's rain adversely affected Mudichur on the outskirts of Chennai. According to The Times of India, Mudichur was of the worst affected areas in the 2015 floods. "The government ought to have taken steps to prevent flooding in Mudichur and other areas which were affected in the 2015 floods. But the present government is worried only about saving the number of MLAs as it has already lost majority," said Stalin to The Times of India.
Lack of storm water drains
In 2015, absence of storm water drains was identified as one of the major causes of the floods. However, even after laying storm water drains, areas continue to get inundated, reported The Times of India. On Tuesday, the civic body boasted that Villivakkam SIDCO Nagar, which was was flooded for 10 days in 2015, was benefitting from the new drains. While claiming Rs three crore was spent on building them, officials continued to use high power pumps to empty water out of the area instead.
As per another The Hindu report, delay in receiving funds for constructing storm water drains continued to pose a major challenge to the level of monsoon preparedness of the city. While the city corporation claims the city is prepared, there has been no improvement in the storm water drain or canal network in the past five years since the Rs 3,000 crore project was proposed in 2012, as per the report.
Reviewing relief and rescue work carried out by Chennai Corporation on Thursday, state revenue minister RB Udhaya Kumar told The Hindu, “We have identified vulnerable locations but cannot prevent waterlogging. However, we can remove the water immediately. These spots should have motor sets, super suckers and JCBs to remove the water and the field-level staff should work efficiently.”
However, the government's response to a flood situation seems to have improved.The Wire reported that after the 2015 floods, the response by municipal bodies to the Cyclone Vardah the very next year was quicker. Nearly 20,000 trees were uprooted at the time. The civic authorities cleared off the trees and restored power, phone and Internet connectivity faster than the previous year.
With inputs from PTI
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Published Date: Nov 03, 2017 13:02 PM | Updated Date: Nov 03, 2017 13:02 PM
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