In November 2021 — indubitably one of the most wettest Novembers in living memory — a appropriate decision of vehicular subways across Chennai suffered from “pleural effusion”, and none as alarmingly because the Rangarajapuram two-wheeler subway and Madley subway.
When other subways had been discharged and joined responsibility, these two had been mute parked in ICU, an prolonged take care of being unavoidable. The “accumulated fluid” being copious, the drainage was exasperatingly sluggish.
The methods for stormwater management spherical these subways had been caught drowsing for the period of the heavy rains, and that they had ended up being guzzlers love Cana Alberano from the “Fairy Tail” animie series.
What came about?
S Rajendran, chief engineer (basic), who has handled many stormwater drain projects, remarks that with regards to depth, a vehicular subway would keep the bottom point in the location it’s located, and rainwater runoffs would waft into the “trough”.
In overall, the first line of defence may presumably well be enough to optimistic these invading flood waters: In customary instances, the effectively or wells lodged in a vehicular subway’s bowels to absorb the rainwater, and the pump home meant for pumping the water out and up to the stormwater drain methods above may presumably well be equal to the duty.
At some point of heavy rains, this association can also collapse love a pack of cards if the stormwater-drainage methods across the vehicular subway fail to bring on their promise.
Rajendran notes that that’s what came about in these subways, and the image of inefficient drainage was starkly evident on the Ranjarajapuram subway.
22 vehicular subways in Chennai
There are 22 vehicular subways in Chennai. Out of them, 16 are maintained by the Better Chennai Company, and the relaxation by the Highways division.
Railway culvert 45
Rajendran notes that there was an evident clarification for this failure.
“On the western aspect of the railway traces crossing the Rangarajapuram vehicular subway, there may be Aziz Nagar, Subramanyapuram and Railway Border Road and the Arcot Road belt, which collectively constitute a wide rainwater catchment situation. The rainwater has to “unhealthy” the railway tune (by accessible stormwater-carrying methods) and attain Mambalam Excessive Road and fling to Bazullah Road and Thirumalai Pillai Road and GN Chetty Road and attain Mambalam canal, right by overlaying a distance of 5 kilometres.
Rainwater from this catchment situation had fully one culvert — railway culvert quantity 45 — to unhealthy over and purchase this lengthy course. This culvert is constricted, being fully one-and-half feet to three feet wide, and two to three feet deep,” the chief engineer explains.
“Attributable to the magnitude of the rains final one year, this culvert can also no longer tackle the inflow of rainwater. The culvert is under the railways’ seek, and need to be maintained and desilted by them. There is a matrix of signalling ca
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