Trishuli River & 26 August 2026 Flash Flood in the Nepal

The Trishuli River (Nepali: त्रिशूली नदी) is one of the major tributaries of the Narayani River basin in central Nepal. The river is formed by the merger of the Kyirong Tsangpo and the Lende Khola originating in Gyirong County of Tibet, which join together near the Rasuwa Gadhi on the Nepal–Tibet border. The valley of the river used to be the traditional trade route between the Kathmandu Valley and Tibet.

1. Source location: Gosaikunda, Rasuwa, Nepal
2. Mouth location: Narayani River
3. River system: Narayani River
4. Left Tributaries: Budhi Gandaki River, Marshyangdi River, Seti Gandaki River
5. Right Tributaries: Zarong-chu

The sources of the Trishuli River lie in the Pekhu Kangri range (called Langtang Himal in Nepal) in Kyirong County in Tibet. Two major rivers, Kyirong Tsangpo (or Kerung Khola) and Lende Khola, merge near Rasuwa Fort at the Nepal border to form the Trishuli river. Trishuli river and its major tributary Langtang Khola merge near Syaphru (or Syapru Besi). Kyirong Tsangpo has a large basin extending beyond the town of Dzongka and numerous streams forming it: Zarong chu, Gyang chu, Prongda chu, Ublung chu, Tsalung chu, Ragma chu etc. After Ragma, it passes through a lush green alpine "Kyirong Valley" (elevation 2700 m) with several villages and Kyirong Town. Afterwards it enters a deep gorge before reaching Rasuwa Fort. The last stretch of the river is part of the Nepal–China border.

Lende Khola has two further tributaries originating in Langtang Himal, Richong Chu and Chusumdo Tsangpo, the latter again forming part of the Nepal–China border.

ven though the Trishuli river is physically formed at Rasuwa Fort, at this stage it is referred to officially by the generic name of Bhot Koshi ("The river from Tibet"). It is called Trishuli Ganga after receiving the Trisuli Khola stream originating in Gosainkunda near Dhunche. This would make Gosainkunda the official source of the river, and the river from Tibet a tributary.

Tributaries Tadi Khola and Likhu Khola join Tishuli near the city of Bidur. The valleys of these rivers provide a link-up to Kathmandu via the pass of Badh Bhangyang. These valleys made up the traditional route between Kathmandu and Tibet.

Proceeding further, Trishuli joins the Narayani River at Devghat. Narayani flows south-west into India and joins the Ganges.

26 August 2026 Flash Flood:

On 26 August 2026, a major flash flood occurred on the river, in particular its upper section at the Tibet border. The flood caused massive damage and loss of life in the Rasuwa and Nuwakot Districts and further downstream, it is considered one of the biggest floods in modern history and is exceptionally severe due to its sheer speed and the extensive damage it caused to infrastructure.

1. The Guardian
2. Wikipedia