Flowing through Sikkim and Darjeeling, the river Tista is the most important river of Sikkim and North Bengal. The importance of the river in the culture and economy of the region can hardly be exagerated. Apart from its varied landscape Tista forms a diverse ecosystem throughout its more than 200kms long journey from high mountainous region of Sikkim to the low land of North Bengal. Tista flows freely, fearlessly and ferociously too. It is fed by the glaciers viz. Zemu, Changame Khanpu, Talung etc.
The River Tista is said to be the lifeline of the Indian state of Sikkim, flowing for almost the entire length of the state and carving out verdant Himalayan temperate and tropical river valleys. The river then forms the border between Sikkim and West Bengal before joining the Brahmaputra as a tributary in Bangladesh. Total length of the river is 315 kilometres.
The river originates from Cholamo Lake at an elevation of 5,330 m (17,487 ft) above sea level in the Himalayas. This lake lies to the north of the Donkia pass near Shetschen, where the summit of the pass is about eight kilometres north-east of Darjeeling. The Teesta River is then fed by rivulets which arise in the Thangu, Yumthang and Donkia-La ranges. The river then flows past the town of Rangpo where it forms the border between Sikkim and West Bengal up to Teesta Bazaar. At Teesta Suspension Bridge, which joins Kalimpong with Darjeeling, the river is met by its main tributary, the Rangeet River. At this point, it changes course southwards flowing entirely into West Bengal. The river hits the plains at Sevoke, where it is spanned by the Coronation Bridge which links the north east states to the rest of India. The river then courses its way to Jalpaiguri and then to Rangpur District of Bangladesh, before finally merging with the mighty Brahmaputra at Fulcherry.
Through its course, river has carved out ravines and gorges in Sikkim meandering through the hills with the hill station Kalimpong lying just off the river. Variegated vegetation can be seen along this route. At lower elevations, tropical deciduous trees and shrubs cover the surrounding hills; alpine vegetation is seen at the upper altitudes. The river is flanked by white sand which is used by the construction industry in the region. Large boulders in and around the waters make it ideal for rafting enthusiasts.
Between the towns of Rangpo and Lohapul, the Teesta flows with a very strong current, ideal for white river rafting. Though an innocuous looking river, the underlying current is very strong. During the monsoons this humble river distends its banks; both in size and turbulence. Landslides in this region often dam up parts of the river in this season.
The Teesta River Flowing across the length of Sikkim, it is fed by snow melting on the mountains as well as rain and meets the river Rangeet at the border between Sikkim and West Bengal.
Changes in the course of rivers
Great changes have
taken place in the course of some of the rivers in Bengal and the adjoining
areas, during the period since 1500 AD. Although positive evidence is
lacking, similar changes can be assumed in the remoter past. The Teesta is
one of the rivers that has changed over the years.
The Teesta earlier ran due south from Jalpaiguri in three channels, namely, the Karatoya to the east, the Punarbhaba in the west and the Atrai in the centre. The three channels possibly gave the name to the river as Trisrota (possessed of three streams) which has been shortened and corrupted to Teesta. Of these three the Punarbhaba joined the Mahananda. The Atrai passing through a vast marshy area known as Chalan Beel joined the Karatoya and the united stream joined the Padma near Jafarganj. In the destructive floods of 1787, the Teesta forsook its old channel and rushing south-east it joined the Brahmaputra.