Bhote Koshi in Nepal and Poiqu in Tibet (both names roughly mean "Tibetan river") is the name given to the upper course (main tributary) of the Sun Kosi river. It is part of the Koshi River system in Nepal.
Bhote koshi is the Nepalese name (). In Nepali language, the word "bhoá¹Âe" or "bhoá¹ÂiyÃÂ" means Tibetan; and the word "kosi" means river. As such, the name is not unique, the western tributary of the upper Sapta Koshi is also called Bhote Koshi.
It was called Po Chu () by early 1990s Everest expeditions, which name means the "river of Tibet." It is spelt Poiqu or Boqu () in Chinese sources.
The Tibetan name of the river is Matsang Tsangpo ().
The headwaters of the Poiqu and Bhote-Sun Koshi River are located at the Zhangzangbo Glacier in Tibet. The river flows out of the Lumi Chimi lake. When entering Nepal, it is called the Bhote Koshi. Further downstream, from the village of Bahrabise onwards, it is called the Sun Koshi.
In July 1981, a sudden ice avalanche caused a Glacial Lake Outburst Flood in the moraine-dammed Zhangzangbu-Cho Lake in the headwaters of the Bhote Koshi. The ensuing debris flow destroyed bridges, and sections of both the Arniko and the NepalâÂÂChina highways.
The Bhote Kosi is used for both rafting and kayaking. It is the steepest river rafted in Nepal, with a gradient of 15 m per km. Bungee jumping or swinging over the Bhote Kosi has been described as the âÂÂultimate experienceâÂÂ.
The river carves a steep and direct drop at the top that gradually eases to more placid streams and calmer pools with a 46-km run at the Lamosunga dam. The rapids are class IV-V at high flow, and III at lower levels. The river is steep and continuous with one rapid leading into another.