Arun River
Major transboundary Himalayan river rising on the Tibetan Plateau and flowing through Nepal to feed the Koshi system; important for hydrology, ecology, communities and hydropower potential.
The Arun River is a major Himalayan watercourse that rises on the Tibetan Plateau, where it is known locally as Phung Chu or Bum-chu, and flows south into Nepal before joining other rivers to form the Koshi system that continues into India. In Nepali usage the river is known by forms recorded in regional languages; see the Nepali name for regional variants. The Arun is notable for a very steep descent from high plateaus into deep Himalayan gorges, producing high-energy flows and a strong seasonal contrast between low winter discharge and high monsoon flows.
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Course and geography
The Arun originates in eastern Tibet and flows broadly southward into eastern Nepal. Once in Nepal it cuts through deep valleys and then meets other major Himalayan tributaries — including the Sun Kosi and Tamur — to help form the Koshi basin, which continues across the plains into India. The river basin covers a wide range of climates and elevations, from glaciated headwaters and alpine meadows to subtropical valleys and lower floodplains.
Hydrology and significance
The Arun is among the principal contributors to the Koshi system, supplying a substantial portion of its total discharge (commonly cited as about one third). Its flow regime reflects a mix of glacier and snow melt at high elevations together with strong summer monsoon rainfall, which drives peak flows and seasonal flooding. The river also transports large sediment loads downstream, shaping floodplain dynamics and affecting river management in Nepal and downstream in India.
Ecology, people and uses
Valleys along the Arun support diverse habitats and traditional human livelihoods. Highland areas provide grazing and alpine flora, while lower slopes and floodplains sustain forests, agriculture and riparian communities. People use the river for irrigation, potable water, small-scale fisheries and local transport; its gradient and flow have long attracted attention for hydropower development and regional planning.
Names, history and transboundary issues
Known as Phung Chu or Bum-chu in Tibet and by local forms in Nepal, the Arun has cultural as well as practical importance across national borders. Shared concerns include flood risk management, sedimentation, cross-border water cooperation and the environmental impacts of proposed hydropower projects. Coordinated planning and monitoring are commonly recommended to balance development, flood protection and conservation in this transboundary basin.
Key facts
- Origin: Tibetan Plateau (Phung Chu / Bum-chu)
- Role: principal tributary contributing a significant share of Koshi discharge
- Drivers of flow: glacier/snow melt and summer monsoon
- Uses and issues: irrigation, hydropower potential, sediment transport, flood management
Related articles
Author
AlegsaOnline.com Arun River Leandro Alegsa
URL: https://en.alegsaonline.com/art/6394
Sources
- thehimalayantimes.com : details about flood and problems caused by river
- mountaindelights.com : Details about rafting in arun river