Showers and tide threaten waterlogging
Parts of Kalighat and Bodyguard Lines in Alipore were flooded on Friday and several other pockets of Calcutta could witness such inundation as the weather office forecast more rain from Sunday, officials and engineers of the Calcutta Municipal Corporation (CMC) have warned.
The continuous rain for several days has already raised the level of the Hooghly. The height that the Hooghly’s water reaches during high tide in August and September is more than that in the rest of the year.
“There could be waterlogging if it rains heavily and during the high tide hours,” a CMC engineer said on Friday afternoon.
“During high tide, the sluice gates that drain out water from the city’s drainage network are kept closed to prevent entry of Hooghly water into the network. Usually, the sluice gates are kept closed for at least an hour before and after the peak of the high tide,” said a CMC engineer.
“But in August and September, the gates are kept closed for a longer duration as the level of water is higher during high tide.”
The sluice gates are operated to drain out water from the underground drainage network into the Hooghly in the west and Bidyadhari river in the east.
The city received over 115mm of rain between August 17 morning and August 21 morning under the influence of a low-pressure area that had formed over the Bay of Bengal on Wednesday.
“The system has lost strength and travelled towards central India. But a new low-pressure area is likely to form over the north Bay of Bengal on Sunday. Under its influence, widespread rain is expected in south Bengal. One or two places, including Calcutta, might get heavy rain from Sunday,” said a Met official.
“The monsoon trough still passes through south Bengal. The monsoon currents are strong and are expected to trigger rain on Saturday as well,” said G.K. Das, the director of IMD Calcutta.
The city sky remained overcast throughout Friday and there were multiple spells of rain. The incessant rain that the city had witnessed over the past few days was missing.
A resident of Kalighat said water in the Adi Ganga had breached banks and flooded roads nearby during high tide on Thursday. “It happens every year quite a few times in August and September. And if high tide is accompanied by heavy rain, waterlogging endures for some time,” said the resident.
Tarak Singh, a member of Calcutta Municipal Corporation board of administrators in charge of drainage, said the civic body had kept ready 650 portable pumps to drain out water from low-lying areas. “All 74 drainage pumping stations have been kept ready, too, so they can work in full capacity,” he said.
The civic body also employs teams of people who clean the mouth of gully pits on flooded roads so the accumulated water could flow into the underground drainage network. The men also open man-hole covers to quickly drain out water. “There is some shortage of personnel because of the pandemic but we have kept teams ready in the boroughs,” said one CMC engineer.
Vast portions of the Sunderbans riverine belt were inundated because heavy rain, accompanied by tidal waters, breached earthen embankments in North and South 24-Parganas. The water levels in the Roymangal, Bidyadhari, Kalindi and Goureshwar rivers have risen, said district officials.
Additional reporting by Subhasish Chaudhuri