As rains lash Chennai, is there cause for worry? Not yet, say experts

Our reservoir levels are still low, the rainfall patterns are different – and crucially, the state says it’s better prepared than it was in December 2015.

news Rain

Arjunan, a resident of Kannan Avenue in Mudichur in Chennai, has been growing worried by the hour. The streets in his area are flooded with rain water since Sunday morning, and Arjunan is anticipating a repeat of the 2015 Chennai floods that ravaged the city. “We have been wading through knee-deep water now. Half the residents – mainly those living in rented homes – have left their houses. What will people like us do? If it is just rain water alone, then there is no problem. But if the reservoir overflows then our situation will worsen,” says the 40-year-old.

“We are awake now, but we won’t know what might happen in the night. We won’t know when they will breach the bunds in lakes and ponds to let out excess water. News channels keep flashing that heavy rains are expected to continue. As you can see the weather too is unpredictable. It is worrying,” he adds. Arjunan who also owns a tailoring unit suffered severe losses in 2015 with water entering both his house and unit.

Mudichur, photo courtesy: Arjunan

Palaniswamy of Madipakkam who did not go through a severe crisis like Arjunan did in December 2015 is however worried this time around. Having reported flooded streets to Chennai Corporation on Sunday, Palaniswamy awaits as Corporations workers try and fix the sudden flooding in his street. “So far we’ve never had a problem. They recently laid roads but did not fix storm water drains. New buildings have come up too. Draining of rain water has now become a problem,” he explains.

Palaniswamy and Arjunan are among the thousands of Chennai residents who are viewing the city’s current weather with growing concern. December dawned with heavy showers this Sunday and residents of Chennai had every reason to turn anxious. Just four years ago around the same time, the city witnessed its worst flooding, causing severe damage to lives and property.

Madipakkam, Palaniswamy

Chennai has recorded a deficit of 30% rainfall so far, during the North-East Monsoon season that began on October 1. However, continuous showers for the past two days have resulted in water-logging in many parts of the city. Therefore, when visuals of waterlogged roads and steady showers were shared on social media, memories from the not-so-distant past worried residents who expressed their fears over a repeat of 2015.

But experts say that there is no cause for worry just yet.

‘No need for worry’

Explaining how rainfall in 2015 was different from this time around, Weather blogger Srikanth says, “It can’t be 2015. In 2015, we had two or three heavy spells of rainfall before December. December saw the third heavy spell of rainfall in 2015. In 2015 we had rain almost every other day, continuously in November. This time, November was almost entirely dry. Moreover lakes are not full yet.”

He also notes that such heavy rainfall occurring during a short span of time is the consequence of climate change. “Rainfall pattern is going through a change. Rain is concentrated for a fewer number of days and we have longer spells of drought. This is a consequence of global warming and will become a common occurrence. We will have to find ways to work around this,” he points out.

An official from Metro Water Department says, “Our lakes are less than half full right now, so there’s no need to panic. When there’s a large quantity of water flowing out from storm water drains and when the sea level too increases, it may take some time for water to drain and recede. Temporary flooding will be there, but it is nothing to worry about.”

He further adds that the city is better prepared this time around “Infrastructure is definitely better than it was in 2015,” he says.

Reiterating this, Revenue Secretary J Radhakrishnan says that what happened in 2015 will not repeat this year. “We are monitoring the situation round the clock,” he tells TNM, “All districts and corporations are alert – especially to address the inundation of the standard low lying areas. Revenue administration is in touch with all Collectors, PWD, local bodies, Health, Agriculture and Animal husbandry departments, TNEB, TWAD, Metro and transport department among others.”

Reservoir levels

Water storage levels of past and present too show that there’s no cause for immediate worry. The full capacities of the four main reservoirs that supply water to Chennai are as follows: Poondi can hold 3,231 Mcft, Cholavaram can hold 1,081 Mcft, Redhills can hold 3,300 Mcft and Chembarabakkam can hold 3,645 Mcft.

On December 1 in 2015, the storage level at Poondi reservoir was 2,745 Mcft. In Cholavaram it stood at 595 Mcft while at Redhills reservoir water levels were at 2,790 Mcft. Chembarambakkam levels were at 3,141 Mcft. In the aftermath of the 2015 floods, several reports had highlighted how failure to ensure timely release of water from the Chembarambakkam Lake in Chennai during the Northeast monsoon season had resulted in the floods.

The storage levels today – on December 1, 2019 – show that the reservoirs are not even half full. Poondi’s level as of December 1 is at 989 Mcft, at Cholavaram the level is 96 Mcft, Redhills reservoir holds 1,639 Mcft and Chembarambakkam has 749 Mcft water. The combined storage levels of all four are at 3,473 Mcft while the combined total storage capacity is 11,257 Mcft. So our reservoirs have only reached 30.85% of the total capacity.

Interestingly, levels are higher this time than last year’s storage levels. In 2018, Poondi had 381 Mcft water while Cholavaram had 40 Mcft, Redhills had 1,102 Mcft and Chembarambakkam’s level stood at 185 Mcft.