This year the rains in the southern part of India came in a week early than last year but were much harsher and heavier this time. It was thus sweetly ironical that Chennai was in a much better condition than last year. Thanks to the new stormwater drains built by the state government, Greater Chennai Corporation and other stakeholders. Without them Chennai would have been completely submerged.
In comparison to last year’s 15 cm rainfall, this year the city witnessed an average rainfall of 25 cm. However, in such severe conditions 14 out of 15 zones were completely free from water logging and traffic jams. To give a detailed knowledge about how Chennai Corporation, under the supervision of Commissioner Gagandeep Singh Bedi, managed the water condition in the city, Indian Masterminds spoke to IAS officer M S Prasanth who is currently posted as DC (Works) in the GCC.
GOVERNMENT CAME IN SUPPORT
Mr Prasanth said, “After last year’s flooding, the Government of Tamil Nadu set up an advisory committee to study the complicated drainage system of Chennai, as it has a lot of gradient issues due to being a flat city and closer to the sea. The committee visited all the dark spots and gave their recommendations. Most of the works that are being executed this time are on the basis of the interim report prepared by the committee, which included short term solutions for the drainage problem of the city.”
Based on the recommendations, the government sanctioned 700 crores for the construction of stormwater drains in the city. Construction of around 220 km of drainage network was taken up on priority within the core city of Chennai. Mr. Prasanth said, “Typically completion of a project of this magnitude takes up to three years, however, as this was an urgent issue for the government, looking at the floods which took place last time, the target to complete the work was set from May to 30 October, 2022.”
“As the project was speeded from a three-year timeline to just one year, we prioritized the construction of 158 km. To make this unbelievable thing possible, our engineers, monitoring officers, elected representatives, and the entire missionary worked as one unit,” he added.
WORKING ON WARFOOTING
To expedite the works, the corporation started advanced procurements so as it takes lesser time than just waiting for tenders to sanction. Mr. Prasanth said, “We saved around a couple of months of procurement by going for advanced tendering. Secondly, as per the recommendations of the committee, we have taken up 10 more packages where there is area level flooding. We have involved IIT Madras to work on the hydraulic modelling of these 10 packages. The technical work was done by the consultants of IIT Madras who helped in draining the water efficiently.”
Thirdly, there were isolated problems where streets were flooding due to excess rainfall. In these scenarios, despite using any other models, the water needed to be drained from one street to another. These were solved easily by the corporation engineers who diverted the water flow to other streets.
Lastly, the main work which needed to be done alongside construction of stormwater drains was the desilting and rehabilitation of existing drainage network. Mr. Prasanth said, “We already have a 2000 km stormwater drainage network and additionally now 1000 km is under construction. However, the existing network is also very critical due to which it has to be desilted and minor rehabilitation need to be done in these drains. Additional money was sanctioned and work started way early on new storm water drains.”
Apart from this, the desilting of the major water courses was done by the Water Resource Organisation effectively.
RESULTS
As compared to last year, Chennai witnessed almost no traffic jam due to heavy rainfall. Also, the 10 subways which had to be closed last year during the monsoon, only two of them were stuck this time due to pumps’ failure.
Only 50 locations were under water and tree fall witnessed at 35 locations this year while 167 locations were submerged at the end of the first-day spell. Greater Chennai Corporation had to deploy about 1,200 motor pumps to clear water last year. Whereas, on Tuesday, the civic body had to press only 156 pumps into service.
Mr. Prasanth ended by saying, “The city would have absolutely flooded if all of these initiatives were not taken on war footing.”
