Kharkai river in spate on Monday. Picture by Animesh Sengupta

Jamshedpur, which received an average rainfall of 15mm in the past 24 hours, got its first scare of flash floods on Monday morning in low-lying areas near Kharkai for a manmade reason — the release of waters from Bankabal dam, Odisha’s Mayurbhanj district.

As a sluice gate of the dam opened, waters from Odisha flowed to Kharkai and then, as a ripple effect, to Subernarekha as well.

On Monday evening, Kharkai was flowing at a height of 130.80 metres in Adityapur, a little below its danger mark of 139 metres. Subernarekha, at 120.46 metres, nearly touched its danger mark of 122 metres.

As the Met office has announced depression-induced rains for 48 hours more, and Bankabal is yet to close its sluice gate, there is imminent danger of flash floods in low-lying areas close to Kharkai and Subernarekha.

A preview was seen immediately as Kharkai’s swelling waters swamped low-lying areas of Bagbera’s densely populated Nayi Basti, on the city fringes off Jugsalai, barely 40 metres away from the river. Some 30 houses of Nayi Basti got submerged.

“Efforts are on to rescue people whose houses are submerged,” said Bagbera Mahanagar Vikas Samiti senior functionary Subodh Jha.

East Singhbhum additional deputy commissioner (ADC) Ganesh Kumar said a sluice gate of Bankabal dam opened at 7am due to heavy rains in Odisha. Sources at flood control cell, Subernarekha Multipurpose Project, said Bankabal dam discharged water at 78.45 cumec (cubic metre per second).

“If Chandil dam radial gates are opened, water will flow down to the Subernarekha, immediately impacting huge residential areas such as Mango, Sonari, Kadma and others,” ADC Kumar said.

Water level at Chandil dam stands at 159.5 metres at present. Radial gates will open only if it reaches 181 metres.

The district administration has prodded Jusco to be prepared for rescue with motorboats, paddleboats and rafts and directed special officers of Jamshedpur Notified Area Committee, Mango Notified Area Committee, Jugsalai Municipality and Jamshedpur circle officer to coordinate among themselves on a 24-hour basis for emergency evacuations.

Officials have also been asked to pre-empt and monitor flash flood management across vulnerable areas.

East Singhbhum district has identified six relief centres in Jugsalai and 12 in Mango — marriage halls, school buildings, health centres and the like — that can accommodate flood victims. All have been kept ready.

Civic officials have also been asked to keep microphones ready in vulnerable areas and issue evacuation announcements if the water level continues to rise in the night.

“The district civil surgeon and civic officials have also been asked to coordinate bleaching powder sprays in waterlogged areas to avoid an outbreak of infections,” said ADC Kumar.