The Tsang Po river also called Yarlung Zangbo River

The Yarlung Zangbo River is the highest major river in the world. Its longest tributary is the Nyang River. In Tibet the river flows through the South Tibet Valley, which is approximately 1,200 kilometres long and 300 kilometres wide. The valley descends from 4,500 meters above sea level to 3,000 meters. As it descends, the surrounding vegetation changes from cold desert to arid steppe to deciduous scrub vegetation. It ultimately transitions into a conifer and rhododendron forest. The tree line is approximately 3,200 metres.