The Lhasa River, also called Kyi River (Tibetan: སྐྱིད་ཆུ་, Wylie: sKyid chu, Chinese: 拉薩河; pinyin: Lāsà hé), is a northern tributary of the Yarlung Tsangpo River in the south of the Tibet Autonomous Region of China. The Yarlung Tsangpo is the upper section of the Brahmaputra River. The Lhasa River is subject to flooding with the summer monsoon rains, and structures have been built to control the floods. In its lower reaches the river valley is an important agricultural area. The city of Lhasa lies on the river.