The Sankosh river absorbed floodwaters released by a glacial lake outburst in Bhutan without causing major inundation in West Bengal’s Alipurduar and Cooch Behar districts, after authorities evacuated more than 10,000 people from vulnerable areas as a precaution.
Residents who spent Thursday night in schools and relief shelters returned to their villages on Friday morning after the immediate threat from the rising river subsided. The administration had shifted people from vulnerable forest villages following the outburst from Shintaphu Lake in Bhutan.
Chief Engineer (Irrigation and Waterways), Northeast, Krishnendu Bhowmik, said the floodwaters began passing through the Sankosh from the early hours of Friday. He was visiting affected areas in Alipurduar and Cooch Behar to assess the situation.
“Based on information from Bhutan’s National Centre for Hydrology and Meteorology (NCHM), received through the Central Water Commission, we anticipated around 7.4 million cubic metres of water. The outburst occurred nearly 200 km from North Bengal,” Bhowmik said.
Officials said water levels in Bhutan rose by around 2 to 2.5 metres following the outburst before excess water flowed downstream towards North Bengal. The additional flow remained within the Sankosh’s natural course, preventing a major flood emergency in the two districts.
Bhowmik said the river was flowing at 44 metres, compared with its High Flood Level of 49 metres, leaving a five-metre margin. The water level and the river’s capacity to accommodate the surge helped limit the impact downstream, according to the official.
Alipurduar Superintendent of Police Amit Kumar Shaw said more than 4,000 people had been moved to schools, while over 6,000 others were shifted to safer locations on higher ground on Thursday night. Food and shelter arrangements were made for the evacuated residents.
The evacuation followed alerts from West Bengal Forest Minister Manoj Kumar Oraon and North Bengal Development Department Minister Nishit Pramanik, who informed the administration about the developing flood risk on Thursday night. Officials then carried out evacuation operations in vulnerable locations.
Bhutan issued an advisory after the October 29 glacial lake outburst, warning of possible further flooding after two artificial lakes formed at Taktsemathang and Taktsi Makhang. Residents along the Mochhu and Punatsangchhu river valleys were asked to avoid riverbanks and flood-prone areas.
The immediate next step for officials in West Bengal is to continue monitoring the Sankosh and assess affected areas, while Bhutan’s advisory remains in force for communities near the identified river valleys.
