The Trishuli River

Context: A catastrophic flash flood originating from a dammed lake in Tibet following a 4.4 magnitude earthquake sent an estimated 20 million cubic meters of excess water surging down the Bhote Koshi–Trishuli–Narayani river system into Nepal.

About The Trishuli River:

What It Is?

• The Trishuli River (Trishuli Ganga) is a transboundary, snow-fed Himalayan river and one of the primary central tributaries of the Gandaki / Narayani River Basin in central Nepal. Culturally named after the Trishula (trident) of Lord Shiva, its valley historically served as the main trade and transit corridor between the Kathmandu Valley and Tibet.

Origin:

• Rises in the Pekhu Kangri range (Langtang Himal) in Gyirong (Kyirong) County, southern Tibet (China).
• Formed by the confluence of the Kyirong Tsangpo (Kerung Khola) and the Lende Khola near Rasuwa Gadhi (Rasuwa Fort) on the Nepal–China border.
• Traditionally associated with the sacred alpine springs of Gosaikunda Lake in Nepal, which feeds the river via the Trisuli Khola near Dhunche.

Course & Flow Path:

• Originates in Tibet at high altitudes and flows through the alpine Kyirong Valley before carving deep gorges along the Nepal–China border.
• Enters central Nepal through Rasuwa District, flowing south through Nuwakot (near Bidur) and Dhading districts.
• Meets the Kali Gandaki at Devghat (Chitwan/Tanahun) to form the Narayani River, which eventually flows into India as the Gandak River before joining the Ganges.

Major Tributaries:

• Langtang Khola: Merges near Syabrubesi.
• Trisuli Khola: Originates from Gosaikunda Lake.
• Tadi Khola & Likhu Khola: Join the main stem near the town of Bidur.
• Bhote Koshi / Kyirong Tsangpo & Lende Khola: Main transboundary upper feeder streams.

Trishuli is a Tributary of: It is a principal upstream tributary of the Narayani (Gandaki) River, which is a major northern tributary of the Ganga River system.

Key Geographical Features:

• High-Altitude Transboundary Catchment: More than 60% of its total drainage basin lies in Tibet. Of its 4,640 sq km catchment area, about 85% lies above 3,000 metres, while 11% lies above 6,000 metres.
• Glacio-Fluvial Hydrological Regime: Heavily fed by snowmelt and glaciers from the Langtang Himal and Mount Ganesh massifs, with around 9% of the basin permanently covered by glaciers and snowfields.
• Deep Gorges & Steep Elevation Drop: Cuts through steep, narrow Himalayan gorges, descending rapidly from over 2,700 m in Tibet to 600 m at Betrawati and lower elevations at Devghat.
• Major Economic & Adventure Waterway: Renowned as Nepal’s most popular white-water rafting destination due to accessible Class III–IV rapids and proximity to the Kathmandu–Pokhara travel corridor and Chitwan National Park.