River Teesta, along with its many tributary streams, is a life line of Darjeeling-Sikkim Hills and downstream plain areas. However, Teesta river system also displays its other aspect with horrific characteristics during monsoon season every year causing severe human-monetary-environmental miseries in the region and lowlands lying downstream. During this period the river becomes a major source of human insecurity.


River Teesta originates from the glaciers of north Sikkim at about 21000 ft. above mean sea level. It flows for about 107 miles in the mountainous region of Sikkim and Darjeeling Himalaya before it emerges at Sevok Railway Bridge into the alluvial plains of Bengal. The river traverses another 60 miles on North-Bengal plains and enters into Bangladesh. Thereafter it flows for a length of about 83 miles in Bangladesh before joining the mighty Brahmaputra at Chilmari in North West Bangladesh.



While Teesta itself is a tributary river of mighty Brahmaputra the principal tributaries of Teesta include rivers like the great Rangit, Lish, Gish, Cheel, Neora, Relli etc. Almost all of them flow through Darjeeling and Sikkim Hills. The flows of Teesta River vary widely between different seasons. While the peak flood flow during the monsoon months (June-September) rise up to 0.5 million cusecs, the dry season flow dwindles to a mere 5,000 cusec during the dry season (in the month of February).




According to Hunter’s Statistical Account of Bengal, Teesta was originally a river of Ganga basin. The Teesta River which at present times flows down from the Darjeeling and Sikkim hills into Bangladesh to meet up with the Brahmaputra used to flow into the Mahananda and the Ganga in Bihar about 220 years ago. In 1787, due to heavy flood and devastating earthquake Teesta shifted its course to Brahmaputra basin. If such sudden river capture occurs today, it will sweep away thousands of villages in a gigantic flash flood.