Dharla River

The Dharla River (ধরলা নদী) is a tributary of the Brahmaputra which is a trans-boundary river flowing through India, Bhutan and Bangladesh. It originates from Kupup/Bitang lake lying in Pangolakha Wildlife Sanctuary of East Sikkim in the Himalayas where it is known as the Jaldhaka River. It then flows through East Sikkim, India then goes to Samtse District, Bhutan and returns to India again at Kalimpong district. From there, it flows through Jalpaiguri and Cooch Behar districts of West Bengal, India, one of the seven main rivers to do so. Here the river enters Bangladesh through the Lalmonirhat District and flows as the Dharla River until it empties into the Brahmaputra River near the Kurigram District. Near Patgram Upazila, it again flows easterly back into India. It then moves south and enters Bangladesh again through Phulbari Upazila of Kurigram District and continues a slow meandering course.

The average depth of river is 12 ft and maximum depth is 39 ft, in origin of Kurigram.

Erosion by the rivers Dharla and Jamuna took a serious turn in Lalmonirhat in 2007. In Lalmonirhat, about 2 km of a 7 km long flood control embankment was devoured by the Dharla. Three mosques, two temples, a madrassah and a primary school, and a vast tract of cultivable land with crops were devoured by the river, rendering about three thousand people homeless.

There is a park beside the Dharla at Kurigram. There also is a bridge. The river is full during the monsoon season but has only knee-deep water in summer. Deposition of silt has led to the formation of many small islands (chars) in the river.

Floods
River Dharla, along with River Teesta have created major flooding multiple times in Bangladesh during monsoon season between June and September.